Selectivity in Non-Directed C H Functionalization of sp 3 C H Bonds
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- Stanley Clarke
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1 Selectivity in on-directed C Functionalization of sp 3 C Bonds aromatic C primary C benzylic C Ac secondary C α-heteroatom C tertiary C gan Shaw MacMillan Group eting
2 C Functionalization: Challenges for Selectivity and eactivity aromatic C primary C benzylic C Ac secondary C α-heteroatom C tertiary C unactivated aliphatic bonds have high bond strengths low bond polarity - no lone pair/π-orbitals to interact with metal catalyst many C bonds in each molecule - hard to target specific bond non-directed often thermodynamically less favored that directed
3 C Functionalization: Challenges for Selectivity and eactivity aromatic C primary C benzylic C Ac secondary C α-heteroatom C tertiary C unactivated aliphatic bonds have high bond strengths Why low bond is so polarity much research - no lone pair/π-orbitals effort focused to toward interact C with activation? metal catalyst many C bonds in each molecule - hard to target specific bond non-directed often thermodynamically less favored that directed
4 C Functionalization: A Strategy for Streamlining Synthetic Sequences FG FG FG Ac FG Ac FG FG direct C functionalization single differentially substituted product Benefits of C Functionalization: allows streamlining of synthetic routes - more atom economical direct functionalization of light alkanes to valuable feedstocks late stage functionalization of natural products and pharmaceuticals no requirement for pre-installation of functional groups
5 C Functionalization: Presentation utline Concerted M Bond Formation Functionalization via adical Generation hν, ML n or reagent FG C Ir C L Ir C Cleavage via Insertion of tal Carbenes h C δ +
6 C Functionalization: Presentation utline Concerted M Bond Formation Functionalization via adical Generation hν, ML n or reagent FG C Ir C L Ir C Cleavage via Insertion of tal Carbenes h C δ +
7 C Functionalization via Concerted M C Bond Formation M X[M]L n, -X concerted metalationdeprotonation (CMD) [M]L n oxidative addition M What factors influence selectivity when C activation proceeds via concerted M C bond formation?
8 C Functionalization via Concerted M C Bond Formation Bergman and Graham: alkane C oxidative addition 3 P Ir or C Ir C hν, - 2 L Ir JACS 1982, 104, 352.; JACS 1982, 104, 3723 L Ir L Ir equilibration studies indicated thermodynamic preference for C activation: aryl > > primary C > secondary C Buchanan, J. M.; Stryker, J. M.; Bergman,. G. JACS 1986, 108, 1537
9 C Functionalization via Concerted M C Bond Formation Bergman and Graham: alkane C oxidative addition 3 P Ir or C Ir C hν, - 2 L Ir JACS 1982, 104, 352.; JACS 1982, 104, 3723 L Tp h L Tp h C BDE (kj mol -1 ) M relative bond strength k rel phenyl methyl n-pentyl c-hexyl increasing C BDE increasing M BDE increasing rate of ox add. Jones, W. D.; Feher, F. J. Acc. Chem. es. 1989, 22, 91.
10 Catalytic C Borylation of Alkanes Stoichiometric Borylation of Alkanes W B C C C hν, n-bu Bcat Bcat Bcat 85% yield 74% yield 22% yield Waltz, K. M.; artwig, J. F. Science 1997, 277, 211. Catalytic Borylation of Alkanes 5 mol% Cp*h(η4-C 6 6 ) n-hept n-hept Bpin 150 C 84% yield Chen,.; Schlecht, S.; Semple, T. C.; artwig, J. F. Science 2000, 287, Jones, W. D.; Feher, F. J. Acc. Chem. es. 1989, 22, 91.
11 Catalytic C Borylation of Alkanes 5 mol% Cp*h(η4-C 6 6 ) Bpin B 2 pin 2, 150 C alkane borylated product tbu Bpin Bpin F 7 Bpin Bpin 91% yield (48% yield) 74% yield (70% yield) 83% yield (46% yield) 55% yield (67% yield) nbu Et nbu Bpin Bpin Et 3 preferential functionalisation of more electron-deficient unhindered C bond 4:1 regiomeric ratio Lawrence, J. D.; Takahashi, M.; Bae, C.; artwig, J. F. JACS 2004, 126,
12 Catalytic C Borylation of Alkanes alkane h Bpin C bond cleavage generation of reactive 16 e- h-complex pinb h L h pinb Bpin h Bpin isomerisation B 2 pin 2 -Bpin Bpin borylated alkane h pinb C B bond formation h Bpin Wei, C. S.; Jimenez-oyos, C. A.; Videa, M. F.; artwig, J. F.; all, M. B. JACS 2010, 132, 3078.
13 Selectivity for Primary C Borylation alkane h Bpin C bond cleavage generation of reactive 16 e- h-complex pinb h L h pinb Bpin h Bpin isomerisation B 2 pin 2 -Bpin Bpin borylated alkane h pinb C B bond formation h Bpin Wei, C. S.; Jimenez-oyos, C. A.; Videa, M. F.; artwig, J. F.; all, M. B. JACS 2010, 132, 3078.
14 Selectivity for Primary C Borylation h pinb h Bpin C bond cleavage σ-bond metathesis TS boron p-orbtial implicated pinb h n-hept C 2 D D h Bpin pinb D 1:1 octane cyclohexane 8 h 0.87 D-incorporation D 0.15 D-incorporation reversible insertion enables generation of thermodynamically favoured C cleavage complex Wei, C. S.; Jimenez-oyos, C. A.; Videa, M. F.; artwig, J. F.; all, M. B. JACS 2010, 132, 3078.
15 Catalytic C Borylation of Alkanes alkane h Bpin C bond cleavage generation of reactive 16 e- h-complex pinb h L h pinb Bpin h Bpin isomerisation B 2 pin 2 -Bpin Bpin borylated alkane h pinb C B bond formation h Bpin Wei, C. S.; Jimenez-oyos, C. A.; Videa, M. F.; artwig, J. F.; all, M. B. JACS 2010, 132, 3078.
16 Catalytic C Borylation of Alkanes generation of reactive 16 e- h-complex alkane h Bpin C bond cleavage pinb h 1 alkane L h pinb Bpin h Bpin isomerisation B 2 pin 2 Bpin borylated alkane -Bpin h pinb C B bond formation h Bpin Wei, C. S.; Jimenez-oyos, C. A.; Videa, M. F.; artwig, J. F.; all, M. B. JACS 2010, 132, 3078.
17 Catalytic C Borylation of Alkanes 2 alkane 1 alkane pinb h pinb h isomerisation disfavoured isomerisation h Bpin h Bpin Wei, C. S.; Jimenez-oyos, C. A.; Videa, M. F.; artwig, J. F.; all, M. B. JACS 2010, 132, 3078.
18 Catalytic C Borylation of Alkanes (η 6 -mes)ir(bpin) 3, 4 phen Bpin alkane (9 equiv.) B 2 pin 2 (1 eq.), 120 C borylated product Bpin Bpin Piv BF 3 K 83% yield 90% yield 41% yield Bpin Ir Bpin Bpin n-pr BF 3 K Et BF 3 K Bpin 6-membered chelate favours β-cleavage 146% yield 84% yield 39% yield Liskey, C. W.; artwig, J. F. JACS 2012, 134, 12422
19 Catalytic C Borylation of Alkanes (η 6 -mes)ir(bpin) 3, 4 phen Bpin alkane (9 equiv.) B 2 pin 2 (1 eq.), 120 C borylated product Bpin Bpin Piv BF 3 K 83% yield 90% yield 41% yield anticipated site selectivity via radical generation n-pr BF 3 K Et BF 3 K Bpin 146% yield 84% yield 39% yield Liskey, C. W.; artwig, J. F. JACS 2012, 134, 12422
20 Catalytic C Borylation of Alkanes Polymer functionalisation via borylation 2.5 mol% [Cp*hCl 2 ] /a B 2 pin 2 TF/ 2 Bpin Kondo, Y.; Garcia-Cuadrado, D.; artwig, J. F.; Boaen,. K.; Wagner,. L.; illmyer, M. A. JACS 2002, 124, 1164 Direct Functionlization of Benzylic C Bonds 1 mol% IrL(SiEt 3 )Cl Et 3 SiBpin, Cy, 100 C Bpin Ar L :1 rr Ar = 3,5-(CF 3 ) 2 C 6 3 Ar Larsen, M. A.; Wilson, C. V.; artwig, J. F. JACS 2015, 137, Jones, W. D.; Feher, F. J. Acc. Chem. es. 1989, 22, 91.
21 Pt-Catalyzed C Functionalization Shilov process, 1972: PtCl 4 2-, PtCl 6 2-2, 120 C methane methanol 3 C methanol Cl Pt II 2 2 Cl C 4 methane PtCl 4 2-, D 2 D DCl 4, C 3 C 2 D 2 C 3 Cl Pt IV 2 2 Cl Cl Cl Pt IV C 3 2 Cl 2 -Cl Cl Pt II 2 2 C 3 D 25% D D 91% D D D [Pt II Cl 4 ] 2- [Pt IV Cl 6 ] 2-75% D 1.6:1 1 :2 69% D 9:4:1 1 :2 :3 Shilov, A. E.; Shul pin, G. B. Chem. ev. 1997, 97, 2979
22 Pt-Catalyzed C Functionalization (bpym)ptcl 2 S3 2 S 4, 100 C methane methyl bisulfate 71% yield stable to over-oxidation Cl Pt Cl acid-stable complex Periana,. A.; Taube, D. J.; Gamble, S.; Taube,.; Satoh, T.; Fujii,. Science 1998, 280, 560 deactivates proximal C bonds a 3 S PtCl 4 2-, CuCl 2, 2 (90 atm) 2, 2 S 4, 100 C a 3 S sulfonate oxidised product 5:1 selectivity Lin, M.; Shen, C.; Garcia-Zayas, E. A.; Sen, A. JACS 2001, 123, 1000.
23 Pt-Catalyzed C Functionalization n 1 mol% K 2 PtCl 4, 1 equiv. CuCl equiv 2 S 4, air, 150 C n amine oxidised product X n in situ protonation renders substrate soluble in aq reaction medium protects catalysts from coordination to basic amine functionality electronically deactivates proximal C bonds Lee, M.; Sanford, M. S. JACS, 2015, 137, 12796
24 Pt-Catalyzed C Functionalization n 1 mol% K 2 PtCl 4, 1 equiv. CuCl equiv 2 S 4, air, 150 C n amine 5 equiv. oxidised product Piv Piv 65% yield 5:1 rr 122% yield 10:1 rr Piv n Piv Piv Piv Piv n = 1 n = 2 n = 3 n = 4 25% yield, >20:1 rr 85% yield, 10:1 rr 126% yield, 4:1 rr 73% yield, 2:1 rr 87% yield 8:1 rr 88% yield >20:1 rr Lee, M.; Sanford, M. S. JACS, 2015, 137, 12796
25 C Functionalization: Presentation utline Concerted M Bond Formation Functionalization via adical Generation hν, ML n or reagent FG C Ir C L Ir C Cleavage via Insertion of tal Carbenes h C δ +
26 C Functionalization via adical Generation cat cat- substrate ML n FG radical capture radical capture ML n What factors influence selectivity when C activation proceeds through the generation of an alkyl radical?
27 C Functionalization via adical Generation Inductive effects radical stability influences reactivity < < electron-deficient deactivated electron-rich activated 1 2 3
28 Inductive Effects Influence Site Selectivity for xidation alkane 5 mol% Fe(S,S-PDP) Ac, 2 2, C, r.t. alcohol Fe C C Fe(S,S-PDP) alcohol L n Fe III 2 2 L n Fe IV L n Fe V mechanistically similar to metalloporphyrin oxidation pathway rebound mechanism
29 Inductive Effects Influence Site Selectivity for xidation alkane 5 mol% Fe(S,S-PDP) Ac, 2 2, C, r.t. alcohol Fe C C Fe(S,S-PDP) Piv 51% yield 52% yield : X : X X = X = Ac X = Br 1:1 5:1 9:1 X = Ac X = Br 29:1 20:1 57% yield 92% yield Chen, M. S.; White, M. C. Science 2007, 381, 783
30 Inductive Effects Influence Site Selectivity for xidation 3 I 10 mol% Fe(Ac) 2, Ligand C, 50 C 3 ipr ipr alkane azide Ligand 3 3 Ac 3 67% yield, 12:1 r.r 53% yield, 5:1 r.r 50% yield, 10:1 r.r TBS 3 3 TBS 3 53% yield, 10:1:1 r.r 75% yield, 6:1 r.r 24% yield, 5:1 r.r Sharma, A.; artwig, J. F. ature 2015, 517, 600.
31 C Functionalization via adical Generation Inductive effects radical stability influences reactivity < < electron-deficient deactivated electron-rich activated yperconjugation Boc n σ* σ C C-C σ* C
32 yperconjugation Favors Selectivity Adjacent to eteroatoms ML n or reagent FG Boc cat Boc Boc C radical precursor functionalized product AT catalysts Cl S amidyl radical halide radical -centred radical amine radical cation thiyl radical
33 C Functionalization via adical Generation Inductive effects radical stability influences reactivity < < electron-deficient deactivated electron-rich activated yperconjugation Steric effects Boc Ac primary site of oxidation n σ* σ C C-C σ* C secondary site of oxidation [Fe(mcpp)] 17:1 r.r.
34 Strategies for vercoming Substrate Control: -Complexation oxidation amine alcohol Challenges of -eterocycle emote xidation -heterocycles prone to catalyst complexation and/or oxidation to -oxide C bonds adjacent to nitrogen are activated toward functionalization
35 Strategies for vercoming Substrate Control: -Complexation oxidation amine alcohol BF 4 Lewis acid complexation renders basic nitrogen strongly withdrawing
36 Strategies for vercoming Substrate Control: -Complexation 1. protonation/complexation C 2. Fe(PDP), Ac, 2 2 Fe C amine alcohol Fe(S,S-PDP) Et F 3 C C 52% yield 55% yield 40% yield BF 3 C BF 3 F 3 B 65% yield 60% yield 56% yield owell, J. M.; Feng, K.; Clark, J..; Trzepkowski, L. J.; White, M. C. JACS 2015, 137,
37 Strategies for vercoming Substrate Control: -Complexation 1. protonation/complexation 2. Fe(PDP), Ac, 2 2 Fe C C amine alcohol Fe(S,S-PDP) 61% yield 50% yield Ac 42% yield 6:1 ketone:alcohol 66% yield 57% yield owell, J. M.; Feng, K.; Clark, J..; Trzepkowski, L. J.; White, M. C. JACS 2015, 137,
38 Strategies for vercoming Substrate Control: -Complexation White: xidation via radical generation 1. protonation/complexation 2. Fe(PDP), Ac, 2 2 BF 3 amine 65% yield Sanford: xidation via metal C insertion 1 mol% K 2 PtCl 4, 1 equiv. CuCl 2 Piv Piv 5.5 equiv 2 S 4, air, 150 C Piv amine 65% yield 5:1 r.r.
39 Strategies for vercoming Substrate Control: Sterically Bulky Catalysts alkane functionalization selectivity? FG functionalized product typically radical stability favors AT at tertiary centre Can catalyst design override substrate selectivity in radical functionalizations?
40 Strategies for vercoming Substrate Control: Sterically Bulky Catalysts alkane functionalization selectivity? FG functionalized product amidyl radical Schmidt, V. A.; Quinn,. K.; Brusoe, A. T.; Alexanian, E. J. JACS 2014, 136, 14389
41 Strategies for vercoming Substrate Control: Sterically Bulky Catalysts Br Br Br visible light, alkane 2 bromide 3 bromide CF 3 tbu 3,5-(CF 3 ) 2 tbu Br Br Br Br 40:60 2 : 3 78:22 2 : 3 98:2 2 : :1.5 2 : 3 75% yield increasing steric bulk, increasing selectivity Schmidt, V. A.; Quinn,. K.; Brusoe, A. T.; Alexanian, E. J. JACS 2014, 136, 14389
42 Strategies for vercoming Substrate Control: Sterically Bulky Catalysts 3,5-(CF 3 ) 2 Br tbu Br Br visible light, alkane 2 bromide 3 bromide Br Br th 82% 8.3% 53.8% 6.5% 11.5% 13.3% 16.2% 8.4% 50% yield, 12:1 2 : 3 45% yield, >99:1 2 : 3 56% yield 72% yield Br th 70% yield Br 67% yield Schmidt, V. A.; Quinn,. K.; Brusoe, A. T.; Alexanian, E. J. JACS 2014, 136, 14389
43 Strategies for vercoming Substrate Control: Sterically Bulky Catalysts S S 54% yield Et xanthylation FG amidyl radical strategy chlorination Cl 82% yield otoredox-mediated C C bond formation via amidyl radical Ar photocatalyst, phosphate cat. C 2 C 2 CF 3, blue LEDs Choi, G. J.; Zhu, Q.; Miller, D. C.; Gu, C. J.; Knowles,.. ature, 2016, 539, 268 JACS, 2016, 138, 13854; JACS, 2016, 138, 698
44 C Functionalization: Presentation utline Concerted M Bond Formation Functionalization via adical Generation hν, ML n or reagent FG C Ir C L Ir C Cleavage via Insertion of tal Carbenes h C δ +
45 C Functionalization via tal Carbene Insertion ML n 1 2 1,2 insertion 1 2 What factors influence selectivity when C activation proceeds via insertion of a metal carbene?
46 C Functionalization via tal Carbene Insertion M C bond formation does not occur during C bond functionalization ML n Catalytic cycle 1 ML n intermolecular C functionalization with C M bond formation exhibits different chemoselectivity ML n ML n highly reactive and electrophilic acceptor-carbene acceptor/acceptor -carbene low selectivity and substantial dimerisation observed in intermolecular C functionalizations
47 C Functionalization via tal Carbene Insertion M C bond formation does not occur during C bond functionalization ML n Catalytic cycle 1 ML n intermolecular C functionalization with C M bond formation exhibits different chemoselectivity ML ML n n acceptor-carbene donor/acceptor -metal carbene ML n hl n 2 CAr acceptor/acceptor typical structure -carbene highly reactivity reactive modulated and electrophilic by regio-, low selectivity diastereo- and and substantial stereo-selective dimerisation intermolecular observed C in intermolecular functionalizations C have functionalizations been developed
48 C Functionalization via tal Carbene Insertion hl n 1,2 insertion h C δ + alkane alkylated product Key factors effecting regioselectivity highly electrophilic carbene complex build up of partial positive charge in transition state very hindered h 2 (DSP) 4 catalyst commonly used
49 C Functionalization via tal Carbene Insertion hl n 1,2 insertion h C δ + alkane alkylated product Electronic factors: stabilisation of positive charge 93% yield 72% yield TBS Ac deactivated deactivated Davies,. M. L.; Morton, D. Chem. Soc. ev , 1857
50 C Functionalization via tal Carbene Insertion hl n 1,2 insertion h C δ + alkane alkylated product Electronic factors: stabilisation of positive charge > > > > Boc 26, relative rates of rhodium carbene insertion Davies,. M. L.; Morton, D. Chem. Soc. ev , 1857
51 C Functionalization via tal Carbene Insertion hl n 1,2 insertion h C δ + alkane alkylated product Electronic factors: stabilisation of positive charge Steric factors: bulky h-ligands favours primary C insertion > > > > Boc 26, relative rates of rhodium carbene insertion Davies,. M. L.; Morton, D. Chem. Soc. ev , 1857
52 C Functionalization via tal Carbene Insertion hl n 1,2 insertion h C δ + alkane alkylated product Electronic factors: stabilisation of positive charge Steric factors: bulky h-ligands favours primary C insertion C 2 82% yield less activated more accessible TMS TES TBS TIPS TBDPS elative rate Boc more hindered more activated Davies,. M. L.; Beckwith,. E. J.; Antoulinakis, E. G.; Jin, Q. JC 2003, 68, 6126.
53 C Functionalization via tal Carbene Insertion hl n 1,2 insertion h C δ + alkane alkylated product Electronic factors: stabilisation of positive charge Steric factors: bulky h-ligands favours primary C insertion sterically favoured electronically favoured typically site of C insertion for h-carbene Davies,. M. L.; Beckwith,. E. J.; Antoulinakis, E. G.; Jin, Q. JC 2003, 68, 6126.
54 C Functionalization via tal Carbene Insertion 2 [h 2 (DSP) 4 h C δ + alkane alkylated product C 2 Boc C 2 80% yield, 95% ee 67% yield, 91% ee C 2 (p-br) C 2 58% yield, 91% ee 51% yield, 94% ee Davies,. M. L.; Morton, D. Chem. Soc. ev , 1857
55 Enantiocontrol in h-carbene Functionalizations 2 h 2 (DSP) 4 h C δ + alkane alkylated product dirhodium carboxylate core sulfonyl groups h 2 (DSP) 4 D 2 -symmetric Davies,. M. L.; Morton, D. Chem. Soc. ev , 1857
56 Enantiocontrol in h-carbene Functionalizations DSP sulfonate groups block two approach vectors perpendicular ester functionality blocks third vector Davies,. M. L.; Morton, D. Chem. Soc. ev , 1857
57 C Functionalization via tal Carbene Insertion 2 [h 2 (DSP) 4 h C δ + alkane alkylated product C 2 Boc C 2 Boc C 2 C 2 80% yield, 95% ee 67% yield, 91% ee 72% yield, 94% ee 96:4 d.r. 62% yield, 85% ee 80:20 d.r. (p-br) Et C 2 C 2 C 2 C 2 58% yield, 91% ee 51% yield, 94% ee 56% yield, 92% ee 56:44 d.r. 67% yield, 97% ee 74:26 d.r. Davies,. M. L.; Morton, D. Chem. Soc. ev , 1857
58 Diastereocontrol in h-carbene Functionalizations calculated favoured approach Model for diastereocontrol Davies,. M. L.; Morton, D. Chem. Soc. ev , 1857
59 C Functionalization via tal Carbene Insertion 2 [h 2 (DSP) 4 h C δ + alkane alkylated product C 2 Boc C 2 Boc C 2 C 2 80% yield, 95% ee 67% yield, 91% ee 72% yield, 94% ee 96:4 d.r. 62% yield, 85% ee 80:20 d.r. (p-br) Et C 2 C 2 C 2 C 2 58% yield, 91% ee 51% yield, 94% ee 56% yield, 92% ee 56:44 d.r. 67% yield, 97% ee 74:26 d.r. Davies,. M. L.; Morton, D. Chem. Soc. ev , 1857
60 C Functionalization via tal Carbene Insertion Ar 2 C 2 2 C [h 2 (DSP) 4 C substrate secondary selective Can the regioselectivity be altered through catalyst design? S 2 Ar h h 4 4-C 6 4 h h 4 Ar = 4-(C )C 6 4 h 2 (-DSP) 4 increased steric bulk h 2 (-BPCP) 4 Qin, C.; Davies,. M. L. JACS, 2014, 136, 9792
61 C Functionalization via tal Carbene Insertion 2 Ar C 2 h-carbene 2 C C 2 C substrate secondary vs. primary Benzylic Allylic vs. vs. h 2 (-DSP) 4 <1:20 1 :2 h 2 (-DSP) 4 1:7 1 :3 h 2 (-BPCP) 4 5:1 1 :2 74% yield, 92% ee h 2 (-BPCP) 4 17:1 1 :3 60% yield, 94% ee Qin, C.; Davies,. M. L. JACS, 2014, 136, 9792
62 C Functionalization via tal Carbene Insertion 2 Ar C 2 h-carbene 2 C C 2 C substrate secondary vs. primary α-oxy allylic vs. h 2 (-BPCP) 4 h 2 (-DSP) 4 h 2 (-BPCP) 4 3:2 1 :2 >20:1 1 :2 86% yield, 64% ee single regioisomer 88% yield, >20:1 d.r. Qin, C.; Davies,. M. L. JACS, 2014, 136, 9792
63 C Functionalization via tal Carbene Insertion 2 7 alkane C mol% h(ttppp)()() 80 C, neat 7 58% yield 11.4:1 1 :2 bulky porphyrin catalyst h S h(ttppp)()() Thu, -T; Tong, G. S.-M.; uang, J.-S.; Chan, S. L.-F.; Deng, Q.-.; Che, C.-M. ACIE 2008, 47, 9747
64 C Functionalization via tal Carbene Insertion 2 C 2 h-carbene complex A B C alkane regioisomeric functionalized products Selective functionalization of unactivated bonds via catalyst design? h h 1 : 25 : n.d. A : B : C Ar Ar 4 20:1 d.r., 99% ee 99% yield Ar = p-tbuc 6 4 h 2 (-3,5-di(p-tBuC 6 4 )TPCP) 4 Liao, K.; egretti, S.; Musaev, D. G.; Basca, J.; Davies,. M. L. ature 2016, 230, 533
65 C Functionalization via tal Carbene Insertion 2 C 2 h 2 (-3,5-di(p-tBuC 6 4 )TPCP) 4 alkane regioisomeric functionalized products CF 3 CCl 3 CCl 3 tbu CCl 3 Cl 91% yield, 97% ee 15:1 r.r., 14:1 d.r. 91% yield, 99% ee 22:1 r.r., 24:1 d.r. 87% yield, 91% ee 28:1 r.r., 55:1 d.r. CCl 3 Br CCl 3 Br CCl 3 Br Br TMS 82% yield, 91% ee 27:1 r.r., 9:1 d.r. 65% yield, 95% ee 9:1 r.r., 9:1 d.r. 85% yield, 90% ee 20:1 r.r., 9:1 d.r. Liao, K.; egretti, S.; Musaev, D. G.; Basca, J.; Davies,. M. L. ature 2016, 230, 533
66 C Functionalization: Summary Concerted M Bond Formation Functionalization via adical Generation hν, ML n or reagent FG C Ir C L Ir C Cleavage via Insertion of tal Carbenes h C δ +
67 C Functionalization: Summary Concerted M Bond Formation Functionalization via adical Generation highly selective for primary C functionalization currently limited in breadth of functionalizations offers opportunity to modulate catalyst reactivity highly predictable site of C functionalisation wide breadth of transformations developed only moderate catalyst control has been achieved C Cleavage via Insertion of tal Carbenes catalyst design can provide regioselectivity narrower scope of potential products high diastereo- and stereoselectivity achieved
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