Catalytic Asymmetric Allenylation: Regulation of the Equilibrium between Propargyl- and Allenylstannanes during the Catalytic Process.

Achiral substrates 1 and 2 can be regioselectively converted into chiral allenyl alcohols 3 through the title reaction [Eq. (1)] with the synergetic reagent iPrSBEt2 and a chiral TiIV catalyst. The dramatic regioselectivity originates from the regulation of the equilibrium between propargyl- and allenylstannanes during the catalytic process. © 1998 WILEY-VCH Verlag GmbH, Weinheim, Fed. Rep. of Germany.