ja303022d_si_002.pdf (1.75 MB)
Synthesis of Enantioenriched Tertiary Boronic Esters from Secondary Allylic Carbamates. Application to the Synthesis of C30 Botryococcene
journal contribution
posted on 2012-05-02, 00:00 authored by Alexander
P. Pulis, Varinder K. AggarwalEnantioenriched secondary allylic carbamates have been
deprotonated
with sBuLi and reacted with boronic esters. In contrast
to other electrophiles, high α-selectivity was observed and
the boronate complexes were formed with almost complete retention
of stereochemistry. The boronate complexes underwent a stereospecific
1,2-migration leading to tertiary allylic boronic esters with high er (>98:2). The scope of the reaction has been explored
and found to embrace a broad range of both allylic carbamates and
boronic esters. The methodology has been applied to an eight-step,
stereoselective synthesis of each of the diastereoisomers of C30 botryococcene.