1,2-dihalogenoethylene: a general substituted (E)-allylsilanes. CitationTetrahedron Letters, 45(24): 4677-

Transcription

1 \n Title Cobalt-catalyzed mono-coupling of,-dihalogenoethylene: a general substituted (E)-allylsilanes KAMACHI, Taku; KUNO, Akiko; MATSUN Author(s) 専太郎 ; OKAMOTO, Sentaro CitationTetrahedron Letters, (): 677- Date Type Journal Article ights author KANAGAWA University epository

2 Graphical Abstract To create your abstract, type over the instructions in the template box below. Fonts or abstract dimensions should not be changed or altered. Cobalt-catalyzed mono-coupling of SiCH with,-dihalogenoethylene: A general route to γ-substituted (E)- allylsilanes Taku Kamachi, Akiko Kuno, Chikashi Matsuno and Sentaro Okamoto* Department of Applied Chemistry, Kanagawa University -7- okkakubashi, Kanagawa-ku, Yokohama -8686, Japan Leave this area blank for abstract info. ( =, ) mono-coupling exclusively >99% E -M

3 Tetrahedron Letters Pergamon Cobalt-catalyzed mono-coupling of SiCH with,- dihalogenoethylene: A general route to γ-substituted (E)- allylsilanes Taku Kamachi, Akiko Kuno, Chikashi Matsuno and Sentaro Okamoto * TETAHEDON LETTES Department of Applied Chemistry, Kanagawa University, -7- okkakubashi, Kanagawa-ku, Yokohama -8686, Japan Abstract The reaction of trimethylsilylmethylmagnesium chloride (TMSCH ) with,-dihalogenoethylene in the presence of mol% of Co(II) or Co(III) acetylacetonate in THF or THF-NMP proceeded exclusively in a mono-coupling pathway to provide - trimethylsilyl--halogeno--propene with >99% of E geometry in high yield, which was converted to a variety of γ-substituted allylsilanes by Ni- or Pd-catalyzed coupling with organometallic compounds. 0 Elsevier Science. All rights reserved Allylsilanes are versatile compounds in organic synthesis useful as an allylating reagent or a starting material. Therefore, numerous methods have been developed for their preparation, and several substituted allylsilanes as well as simple unsubstituted ones have become obtainable from commercial sources. γ-substituted allylsilane is an important member in the chemistry field that has been widely used in inter- and intramolecular reactions in the presence of a Lewis acid or F - with a variety of electrophiles such as carbonyl, imino and iminium compounds and α,β-unsaturated carbonyl compounds, where high regio- and/or stereoselectivity has often been attained. Therefore, development of a general method for their preparation is desired. Herein we describe an efficient preparation of (E)--silyl--halogeno--propene () by a selective Co-catalyzed mono-coupling of,- dihalogenoethylene with TMSCH (TMS = trimethylsilyl), which allows a general access to (E)-γsubstituted allylsilanes by the metal-catalyzed crosscoupling with a variety of organometallic reagents (Scheme ). First, we investigated a transition metal-catalyzed coupling reaction of (E)-,-dichloroethylene (>99% E), which is commercially available at low price, with TMSCH to find conditions for selective production Scheme * Corresponding author. Tel.: ; fax: ; okamos0@kanagawa-u.ac.jp. ( = ) b ( = ) of mono-coupling product. Thus, (E)-,- dichloroethylene (.0 mmol) was treated with TMSCH (.0 mmol) in the presence of mol% of Ni, Pd, Co or Fe precursor. As can be seen from Table summarizing the results, nickel-catalyzed reactions afforded a mixture of (E)--trimethylsilyl-- chloro--propene () and,-bis(trimethylsilyl)--butene () (entries -). 6 It was noteworthy that the reaction with Ni-PPh complexes gave predominantly (entries and ) but Ni-complexes with a bidentate phosphine ligand such as Ni(dppp) and Ni(dppb) catalyzed production of mainly (entries and ). As shown in entries 6-8, to our delight, the reaction catalyzed by Co(acac) or proceeded smoothly with nearly complete selectivity of mono-coupling to provide in excellent yield, the isomeric purity of which was found to be >99% E by GC and 00 MHz H NM analyses. 7 In these reactions, use of NMP (N-methylpyrrolidin--one) as an additive affected the reaction rate but not the yield and selectivity

4 Tetrahedron Letters (entries 6 and 7). Cahiez originally reported the reaction of,-dichloroethylene with alkyl-grignard reagents providing mono-coupling products exclusively where addition of NMP as a co-solvent was suggested for attaining good yield. 8 The yield of the reaction carried out here was somewhat better than those of the reaction with the usual alkyl-grignard reagents reported by Cahiez. It can be assumed that the absence of β-hydride in TMSCH might avoid other reaction(s) than the desired coupling. With these results, we carried out 0 mmol scale synthesis and could be isolated in pure form by distillation in 90% yield. Pd- and Fe-compounds did not catalyze this reaction (entries and 9). Table a entry c conditions Ni(PPh ) 0 o C, 0 min PPh benzene- Ni(PPh ) PPh 0 o C to r.t.,. h 0 Ni(dppp) 0 o C to r.t.,. h Ni(dppb) 0 o C to r.t.,. h Pd(PPh ) 0 o C to r.t, h THF- 0 trace 87 trace 0 o C, h 86 0 THF Co(acac) d 0 o C, min THF-NMP (:) 0 o C, min THF-NMP (:) Fe(acac) 0 o C to r.t.,. h THF-NMP (:) trace trace SiMe yield, % b a eactions were performed using.0 mmol of Grignard reagent,.0 mmol of,-dichloroethylene and mol% of. b GC yield. c See ref.. equiv of,-dichloroethylene was used. d Tetrahydrate was used. dppp:,-bis(diphenylphosphino)propane dppb:,-bis(diphenylphosphino)butane acac: acetylacetonato 78 Next we tried a Co-catalyzed coupling of TMSCH with (Z)-,-dichloroethylene and, unfortunately, found that the reaction did not proceed at all. However, the results prompted us to carry out the reaction with a mixture of (E)- and (Z)-,-dibromoethylene which is commercially available at low price. Thus, a mixture of E- and Z-isomers of,-dibromoethylene (E:Z = :6, total equiv.) was treated with TMSCH in the presence of mol% of Co(acac) in THF-NMP (Scheme ). As expected, only (E)- -trimethylsilyl--bromopropene (b) was produced in good yield of 7%. Scheme (E:Z = :6, total equiv.) THF-NMP 0 o C, 0 min b 7% yield E only Similarly, γ-halogenoallylsilanes having a silyl moiety other than trimethylsilyl could be prepared without loss of yield and selectivity (Scheme ). 7 Scheme Si THF-NMP Si 78% yield With γ-halo-(e)-allylsilanes and b in hand, we carried out their conversion to by transition metalcatalyzed coupling reactions. As can be seen from Table summarizing the several representative results, with methyl as well as normal and secondary alkyl and aryl groups could be readily prepared by the Ni-catalyzed coupling with the corresponding Grignard reagent (Kumada-Tamao reaction). It is noteworthy that the Suzuki-Miyaura coupling 9 of bromide b with boranes was effective for synthesis of having a functional group as shown in entry. In addition to use of as a substrate for metal-catalyzed coupling reactions, as illustrated in Scheme, and b are useful as an equivalent of -silyl--propynyl and - silyl--propenyl anions. Thus, treatment of with LDA ( equiv.) and the following addition of aldehyde afforded the corresponding adduct, whereas (E)-allylic alcohol was obtained by treatment of b with t-buli and then aldehyde. 0 In conclusion, we have developed a selective monocoupling reaction of SiCH with,- dihalogenoethylene which opens up a general method for preparation of γ-substituted (E)-allylic silanes. Further

5 Tetrahedron Letters study for the preparation and synthetic utilization of functionalized allylsilanes is underway in our laboratories. Table entry 6 7 ( = ) b ( = ) -M (solvent) (mol%) MeMgI () Ni(dppp) () c-c H 9 () Ni(dppp) () 9-BBN CN -M c-c 6 H () 9 Ni(dppp) () d b Mg (THF) Ni(dppp) () n-c 6 H Mg (THF) Ni(dppp) () Pd(dppf) () K PO product a b c Me CN yield, % a 9 b a Isolated yield unless otherwise indicated. eaction was not optimized. b GC yield. 8 9 e ( = H) 9 f ( = Me) 9 g 8 eferences. Langkopf, E.; Schinzer, D. Chem. ev., 99, 9, 7. Weber, W. P. Silicon eagents for Organic Synthesis; Springer-Verlag: New York, 98.. For synthesis of γ-substituted allylsilanes, see: Thibaudeau, S.; Gouverneur, V. Org. Lett., 00,, 89 and references cited therein.. An E- and Z-mixture of or b has been prepared from the corresponding,-dihalopropene by the reaction with SiH and the following methylation with MeMg. For preparation and synthetic utilization of, see: for, (a) Ochiai, M.; Fujita, E. J. Chem. Soc., Chem. Commun., 980, 8. (b) Ochiai, M.; Fujita, E. Tetrahedron Lett., 980,, 69. For b, (c) Nishiyama, H.; Narimatsu, S.; Itoh, K. Tetrahedron Lett., 98,, 89. (d) Angell,.; Parsons, P. J.; Naylor, A.; Tyrrell, E. Synlett, 99, 99. (e) Parsons, P. J.; Angell,.; Naylor, A.; Tyrell, E. J. Chem. Soc., Chem. Commun., 99, 66.. Prepared from TMSCH and magnesium turnings in or THF and titrated by using acid and base. Yields shown in Table and Scheme were based on the amount of the Grignard reagent used.. Tamao, K.; Sumitani, K.; Kumada, M. J. Am. Chem. Soc., 97, 9, One of the authors (SO) reported the preparation of by the reaction shown in entry on Table, in which was obtained by distillation as a benzene solution: Okamoto, S.; Tani, K.; Sato, F.; Sharpless, K. B.; Zargarian, D. Tetrahedron Lett., 99,, H NM (CD, 00 MHz): ; δ.87 (dt, J =, 8. Hz, H),. (d, J = Hz, H),.8 (d, J = 8. Hz, H), 0.0 (s, 9H). b; δ 6.6 (dt, J =, 8. Hz, H),.8 (dt, J =,.0 Hz, H),. (dd, J =.0, 8. Hz, H), 0.06 (s, 9H). ; δ (m, H),.90 (ddt, J =.0,, 8. Hz, H),.77 (dd, J =.0, Hz, H),.7 (d, J = 8. Hz, H), 0. (s, 6H). 8. Cahiez, G.; Avedissian, H. Tetrahedron Lett., 998, 9, Miyaura, N.; Suzuki, A. Chem. ev., 99, 9, Cr -Mediated reaction of b with aldehydes providing δ- trimethylsilyl allylic alcohols has been reported: see references d and e. Scheme b LDA THF then PhCHO t-buli -pentane then PhCHO TMS OH % yield (not optimized) TMS OH 60% yield (not optimized)