Allene synthesis by an asymmetric Baylis-Hillman style reaction on vinylphosphine oxides

A novel reaction has been discovered with a mechanism similar to the Baylis -Hillman reaction. Reaction of a vinylic phosphine oxide with (R)-N-lithio- alpha -methylbenzylbenzylamine 2 in the presence of an aldehyde gave hydrox yphosphine oxides in good to moderate yields and moderate to poor enantiose lectivities. The hydroxyphosphine oxides undergo the Horner-Wittig eliminat ion reaction to produce allenes. Baylis-Hillman reactions of vinylic phosph ine oxides with tertiary amines were also investigated.