Host: Division of Organic Chemistry, The Pharmaceutical Society of Japan
Pages 42-43
We have recently reported that O-silyl cyanohydrins of β-silyl-α,β-epoxyaldehyde (1) can function as a highly functionalized homoenolate equivalent via the tandem sequence involving base-promoted ring opening, Brook rearrangement, and alkylation of the resulting allylic anion. During our investigation of the mechanism of the reaction, we observed that treatment of γ-(t-butyldimethylsilyl)-β,γ-epoxybutyronitrile (2), lacking the siloxy group, with a base in the presence of MeI afforded dimethylated products in addition to monomethylated products. The fact promted us to examine the reaction of 2 with substrates bearing two electrophilic centers in the molecule. When 2 was treated with NaN(SiMe3)2 in the presence of 1,ω-dihaloalkanes, ω-halo-α,β-unsaturated esters, or bis enoates, two cyclization modes were observed depending upon the electrophile and the number of carbon atoms connecting the two electrophilic sites.
