Lee Kang-Sang, Wu Hao, Haeffner Fredrik, Hoveyda Amir H
Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467.
Organometallics. 2012 Nov 26;31(22):7823-7826. doi: 10.1021/om300790t. Epub 2012 Sep 19.
Efficient and highly diastereo- and enantioselective conjugate additions of phenyldimethylsilyl units to acyclic and cyclic dienones and dienoates are disclosed. The C-Si bond forming reactions are catalyzed by 2.0-2.5 mol % of a copper complex of a chiral monodentate N-heterocyclic carbene; the requisite reagent, PhMe(2)Si-B(pin), is commercially available or can be easily prepared. Transformations generate allylsilanes in up to 98% yield and >99:1 enantiomeric ratio, and proceed with complete 1,4-selectivity, unless the dienone or dienoate carries a trisubstituted alkene conjugated to the carbonyl group; in the latter cases, 1,6-addition products are obtained exclusively and in up to >98% Z selectivity.
公开了苯基二甲基硅基单元与无环和环状二烯酮及二烯酸酯的高效、高非对映和对映选择性共轭加成反应。形成C-Si键的反应由2.0 - 2.5 mol%的手性单齿N-杂环卡宾铜配合物催化;所需试剂PhMe(2)Si-B(pin)可商购或易于制备。反应生成的烯丙基硅烷产率高达98%,对映体比例>99:1,且具有完全的1,4-选择性,除非二烯酮或二烯酸酯带有与羰基共轭的三取代烯烃;在后一种情况下,仅得到1,6-加成产物,且Z选择性高达>98%。