Chiral allenes are readily accessed in a single pot operation in the reaction of terminal alkynes, aldehydes, chiral secondary amines, and zinc halides in good yields (up to 77% yield) and excellent enantioselectivities (up to 99% ee) in toluene at 120 °C. The reaction proceeds through initial formation of chiral propargylamine intermediates with creation of a new stereogenic center and subsequent
Zn(II)/Cu(I)-mediated asymmetric synthesis of simple axiallychiral allenes from terminal alkynes and aldehydes was realized by taking advantage of the chiral amine (S)-α,α-diphenylprolinol 3. This one-pot procedure is compatible with broad scopes of both terminal alkynes and aldehydes, providing axiallychiral allenes in practical yields with an excellent enantioselectivity. Control experiments revealed that CuBr