A novel silyl triflate-mediated [2,3]sigmatropicrearrangement of (allyloxy)acetates and their ketene silyl acetals is described, which is proposed to proceed via rarely precedented oxygen ylides. The formal [2,3]Wittlg shift is characterized by the unique stereoselectivity, , the rarely precedented -selectivity and the high erythro-selectivity.
[2,3]Wittig rearrangement of zirconium enolates derived from alkenyloxyacetic acid esters proved to proceed with high -diastereoselectivity, high level of chirality transfer, and exclusive formation of ()-double bond.