Diarylprolinol TMS ether

SCHEME 11.18. Enantioselective aza-Michael additions to enals catalyzed by enantiopure diarylprolinol TMS ether 12. 

The use of enamine catalysis in the enantioselective a-functionalization of carbonyl compounds has been reviewed, including aldol, Mannich, and alkylation processes," and a short review has examined enantioselective a-alkylation of aldehydes Benzodithiolylium tetrafluoroborate (133) is a water-stable salt and can be added enantioselectively to aldehydes at the a-position in the presence of simple chiral organocatalysts, giving the corresponding alcohol. The sulfurs can be readily cleaved with H2/Raney Ni, rendering the process a formal tf-methylation of aldehydes." a ,/3-Unsaturated aldehydes undergo enantioselective a- and y-alkylation via dien-amine activation, using a diarylprolinol TMS ether as catalyst." ... 

Propargylic esters undergo enantioselective alkylation with aldehydes (R-CHjCHO) to give propargylic alkylated products as a mixture of diastereomers (136), using cooperative catalysis by a copper(I)-BINAP complex and a diarylprolinol TMS ether." ... 

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