Methyl 2,6‐di‐O‐benzyl‐3,4‐O‐phenylphosphinediyl‐β‐d‐galactopyran­oside(P—B)­borane with chirality on the P atom

A carbohydrate‐derived optically active P‐chiral dioxo­phenyl­phospho­lane–borane complex, C₂₇H₃₂BO₆P, was prepared from bis­(diethyl­amino)­phenyl­phosphine and methyl 2,6‐di‐O‐benzyl‐β‐d ‐galacto­pyran­oside. The phosphinite was pre­pared with high diastereoselectivity and in good yield. The absolute configuration (R) at the P atom was deduced from the known configuration of the sugar moiety. Weak intermolecular interactions link the mol­ecules into a three‐dimensional network.