高配位シリカートを経由する不斉Lewis塩基触媒反応

抄録

Enantioselective reactions involving hypervalent silicate generated from trichlorosilane derivatives in the presence of chiral Lewis bases as catalysts are reviewed. Highly diastereo- and enantioselective allylations of aromatic and conjugate aldehydes with allyltrichlorosilanes have been developed by using chiral hexamethylphosphoramide (HMPA) derivatives or chiral bipyridine N, N' -dioxide derivatives as catalysts. Enantioselective allylations of aliphatic aldehydes have been accomplished by using chiral dimethylformamide (DMF) derivatives. It is strongly suggested that the present allylations proceed via cyclic chair-like transition structures involving hypervalent silicates. Enantioselective aldol reactions of aldehyde with trichlorosilyl enol ethers have been achieved by using chiral HMPA derivatives, which have been also effective in enantioselective ring opening of epoxides with tetrachlorosilane.