Three in a row! Highlyfunctionalized quaternary amino polyols with three consecutive asymmetric carbon centers have been prepared through tandem hydroboration of allene 1 and addition to an aldehyde (see scheme; Cy=cyclohexyl, TBDPS=tert‐butyldiphenylsilyl, Ts=4‐toluenesulfonyl). This one‐pot process provides access to advanced intermediates for the enantioselective synthesis of α‐substituted serines