Synthesis of acylsilanes from amides and esters, and the selective oxidation of α-silyl alcohols to aldehydes
The acylsilanes 2 can easily be made directly from the dimethylamides 3 by treatment with phenyldimethylsilyllithium. They can also be made in two steps from the esters 4 using 2 equiv. of phenyldimethylsilyllithium followed by oxidation of the disilyl alcohols 5 with PDC. The disilyl alcohols 5 can be used as intermediates in the conversion of esters into aldehydes without recourse to hydride reagents, by monodesilylation, using a Brook rearrangement, followed by oxidation and selective removal of the silyl group, using chromium trioxide in DMSO.