Aldol reaction of allenolates generated via 1,4-addition of iodide anion or its equivalent to α,β-acetylenic ketones

TMSI, Et 2 AlI and (n-Bu) 4 NI/TiCl 4 smoothly added to α,β-acetylenic ketones in a 1,4-fashion to yield allenolates 2 , which reacted with aldehydes providing aldol adducts in good overall yield. A high Z-stereoselectivity was achieved by use of (n-Bu) 4 NI/TiCl 4 at −78°C, while a high E-stereoselectivity occurred at 0°C. Aldol reactions of allenolates, generated via 1,4-addition of an iodide anion equivalent to α,β-unsaturated ketones, are described. A high Z-stereoselectivity was achieved by use of (n-Bu) 4 NI/TiCl 4 at −78°C, while a high E-stereoselectivity occurred at 0°C.