General synthetic method for preparation of optically active propargyl and allylstannanes

The reaction of chiral allenyltitaniums, generated from optically active secondary propargyl phosphates and a Ti(O-i-Pr)4/2 i-PrMgCl reagent, with trialkylstannyl chloride proceeded with a high chirality transfer of more than 93% to afford optically active secondary propargylstannanes in excellent yield, and which, in turn, were converted to optically active (Z)-allylstannanes by reaction with Ti(O-i-Pr)4/2 i-PrMgCl and the following hydrolysis.