JOC: 1985 Year in Review

Transcription

1 Baran Group eting JC: 1985 Year in eview Syntheses discussed: thodoligies discussed: Quadrone 2 C (+)-irsutic Acid C (±) Coriolin (!)-Longifolene (!)-astanecine Manganese (III)-mediated "-lactone annulation William E. Fristad, John. Peterson J. rg. Chem. 1985, 50, Manganese(III)-mediated spriolactonization William E. Fristad, Susan S. ershberger J. rg. Chem., 1985, 50, Manganese(III)-based oxidative free-radical cyclization. Synthesis of (±)-Podocarpic acid Barry B. Snider, aju Mohan, Steven A. Kates J. rg. Chem., 1985, 50, C 2 2 C 3 Lavendamycin thyl Ester Ac C 2 (±)-Vindoline Applications of cyclopropylboranes in organic synthesis. A stereocontrolled route to substituted cyclopropanol derivatives. ick L. Danheiser, Ann C. Savoca J. rg. Chem., 1985, 50, Siloxy-substituted methyl cyclopropanecarboxylates as building blocks in synthesis: efficient one-pot conversion to g-butyrolactones Erich L. Grimm, ans-ulrich eissig J. rg. Chem., 1985, 50,

2 Baran Group eting JC: 1985 Year in eview Total synthesis of Quadrone and Terrecyclic Acid A Paul A. Wender, Donald J. Wolanin ; J. rg. Chem. 1985, 50, ( 3 Si) 2 Li, DME TBDMS 100% TBDMS i 2, nbuli t-bu 2 C C() 2 LDA, TF 81% Ag 3 DMF, 75 C 45% (3 steps) t-bu 2 C 2 CuLi 76% + ab 4 7% TBDMS Si 2 (C 2 ) 2 95% + t-bu 2 C t-bu 2 C Imid S Imid, AIB toluene, 66% t-bu 2 C t-bu 2 C C() 2 Ph 3 PCC 2 80% E:Z=12:1 t-bu 2 C t-bu 2 C C C() 3, Ts 81% E:Z=12:1 C 2 t-bu 2 C C 2 2 C Terrecyclic Acid A neat 195 C JACS, 1980, 102, 4262 Quadrone cat. Al 2 PhC 3, rt 88% C 2 1. a, 2. CS, Pb(Ac) 4 t-bu 2 C tbu 2 C

3 Baran Group eting JC: 1985 Year in eview Total synthesis of Lavendamycin thyl Ester Dale L. Boger, Steven. Duff, James S. Panek, Masami Yasuda J. rg. Chem, 1985, 50, C 2 C C 2 + DCM, rt 54% 2 C 2 C C 2 C 2 Ph Triton-B C % Bn C 2 2 C 2 JC, 1985, 50, 5782 C 2 1. Ac, TF 2. a, TF C 2 1. (g), DCM 2. (S 3 K) % (2 steps) C 2 aqueous work-up 2 C C C 2 DCC DCM 95% (3 steps) C 2 1. a 3, TF PPh 3,DCM; Ac: 2 :TF 31-42% (2 steps) 2 C 2 C 3 LiC 2 S()Ph; then Al(g), TF- 2 Ac C % -, 76% eq. Pd(PPh 3 ) 4 dioxane, 100 C 89% Lavendamycin thyl Ester

4 Baran Group eting JC: 1985 Year in eview 2 C An efficient, enantioconvergent total synthesis of natural irsutic Acid C Andrew E. Greene, Marie-Jacqueline Luche, A. Aarao Serra J. rg. Chem, 1985, 50, C 2 C 2 C 1. (TMS) 2 Li C 2 1. ab 4 2. S 2, 3 ; 2 2 C 1. C 2 2 ; (+)-Ipc 2 B 2 2, a 73% 2. Cr 3 Pyr 2, 94% 2. C 2, K 2 C 3 62% Mg 4, 2 72% 2 C 2 C 2 C 1. Pd 2, Pd(Ac) 2, 60% 2. Al 3, S 97% 2 C S 2 a, 3 82% (3 steps) 1. 2 CC 2 Sb 5 2. DME, 2,! 63% 1. C 3 C, P 3 Zn-Cu; C a 2. ab 4 50% 2. Zn, C 3 C 2 81% 2 C (+)-irsutic acid Intramolecular 1,3-Diyl trapping reactions. A formal total synthesis of (±)-Coriolin Luc Van ijfte,. Daniel Little J. rg. Chem, 1985, 50, mcpba 2. nbuli 52% (2 steps) 1. Bn, Ag 2, DMF 2. DIBAL-, % p-ts, 72% (3 steps) 1. 2 C C K 2C C 2 K DCM, Ac 3. Ac, 2, TF 81% (3 steps) Ph 3 P=C 2, TF 70-80% Ph 1. Bz 2. PCC, DCM C 2 C 2 h" C 3 C 84% 1. 2, Pd() 2 /C Cp, Swern Ac ox. pyrrolidine, 53% (2 steps) e - (g), -1.7 V (SCE) DMF; K, K 3 Fe(C) 6, 2 76% 3. 2 Cu(C)Li, 80% 4. LDA, TMS, Pd(Ac) 2 benzoquinone, C 3 C 40%, 50% rsm (±)-Coriolin

5 Baran Group eting JC: 1985 Year in eview The intramolecular diene-carbene cycloaddition equivalence and an enantioselective Birch reductionalkylation to the chiral auxiliary approach. Total synthesis of (±)- and (!)-Longifolene Arthur G. Schultz, Salvador Puig J. rg. Chem. 1985, 50, C C2 C2 C 2 a, 3, tbu 96% 1. C() 3, reflux I 2. a, 75% (4 steps) 1. DB, toluene; Si 2 ; 85% 2. p-ts, acetone 86% 366-nm benzene C2 C2 C 2 C xylene reflux 90% 1., 2. ac 3 C 3 C 2 Ph 95% toluene reflux C 2 Ph 43% -Acyliminium ion rearrangements:generalities and applications to the synthesis of pyrrolizidine alkaloids David J. art, Tend-Kuei Yang J. rg. Chem., 1985, 50, C 1. ab 4, 83% 2. C, 60% Ac I Ac (!)-Longifolene C Bn Bu 3 Sn AIB Bn 2 Ac 1. Ac 2. Ac 81% Ac 91% Ac Ac LA 90% Bn Ac Ac g, I 2, C 4 85% (!)-astanecine

6 Baran Group eting JC: 1985 Year in eview A new efficient total synthesis of vindorosine and vindoline. Zo Andriamialisoa, icole Langois, Yves Langois J. rg. Chem., 1985, 50, C 2, DCC 2. CF 3 C 2 100% 71% C 2 C 2 + C 2 LDA, TF-MPA C 2 5 I 98% C 2 SC 2 Li TF-DMS 80% S Ts TF/ 2 70% S 1. ab 3 C, + 2. i aney, acetone () 2 C a 79% LA 52% TMS TBAF TMS mcpba C 2 C 2 C 2 C 2 Ac 2, Pyr - 2 quant Ac C 2 + Zn, Ac 2 quant. 89% (3 steps) C 2 (±)-Vindoline

7 Baran Group eting JC: 1985 Year in eview Manganese (III)-mediated!-lactone annulation William E. Fristad, John. Peterson J. rg. Chem. 1985, 50, /3 [Mn 3 (Ac) 7 (Ac)] + 2 Mn(Ac) 2 + Ac Manganese(III)-based oxidative free-radical cyclization. Synthesis of (±)-Podocarpic acid Barry B. Snider, aju Mohan, Steven A. Kates J. rg. Chem., 1985, 50, Mn(Ac) 3 Mn III C 3 C 2 C 2 C 2 C 2 Ac Mn III MnIII Mn III Ac Ac [Mn 3 (Ac) 7 (Ac)] bridging acetate Manganese(III)-mediated spriolactonization William E. Fristad, Susan S. ershberger J. rg. Chem., 1985, 50, C=C 2 + 2/3[Mn 3 ] + C 2 (C) Mn(Ac) Ac C 2 Unsaturated "-keto ester Products Yield % C 2 C 2 C 2 C 2 75 #- 41% "- 8% Entry Alkene Yield, % 1. 1-hexene octene allyl chloride cyclohexene 16 C 2 C 2 C 2 unsat 36 sat 10 xn. cond.: 2 eq. Mn(Ac) 3, 1 eq. Cu(Ac) 2, 1h at 60 C

8 Baran Group eting JC: 1985 Year in eview Applications of cyclopropylboranes in organic synthesis. A stereocontrolled route to substituted cyclopropanol derivatives. ick L. Danheiser, Ann C. Savoca J. rg. Chem., 1985, 50, eq. nbuli at -100 C 2 2, a 3 4 Entry Substrate Borane Products Yield, % Bn then BZ 2, warming BZ B B Bn 3 Bn 93 : Siloxy-substituted methyl cyclopropanecarboxylates as building blocks in synthesis: efficient one-pot conversion to g-butyrolactones Erich L. Grimm, ans-ulrich eissig J. rg. Chem., 1985, 50, Si 4 1 C KB Entry Substrate Product Yield, % 1. C Si 3 Si C B 3 B C 3 Si Bn 3 B Bn Si C 2 89