Stereoselective preparation of P,axial-stereogenic allenyl bisphosphine oxides via chirality-transfer

P,C-Stereogenic propargyl alcohols R-C-3/S-C-3 ' were prepared by the addition of (L)-menthyl-derived SPOs to propynals, which were converted to P,axial-stereogenic allenyl bisphosphine oxides. The chirality transfer was controlled by alpha-carbon via syn [2,3]-sigmatropic rearrangement. For S-C-3 ' linking weak WDG on the alkynyl moiety, the chirality on the axis depended on stereogenic phosphorus.