Stereocontrolled synthesis of highly functionalized quaternary carbon centers: a route to alpha-substituted serines.

ABSTRACT

Three in a row! Highly functionalized 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 alpha-substituted serines.