Allenoate Prenucleophiles: A Triply Diastereoselective Approach to β-Hydroxy Esters Containing All-Carbon α-Quaternary Centers

Abstract

Allenyl esters activated by titanium­(IV) underwent additions to a wide range of aldehydes in high regio- and diastereoselectivities leading to products containing an all-carbon quaternary center bearing an α-vinyl group that was installed with high selectivity for the Z-geometry. An aldol product was also converted to an indanone offering a new route to this important compound class. Product triple diastereoselectivity has been rationalized using a concerted transition-state model.

Reductive coupling of allenoates with aldehydes catalyzed by halogenotin hydride

“…Herein, we report the details of the hydrostannylation of allenoates with Bu 2 SnClH and a subsequent application to coupling with aldehydes. [25][26][27] The tin reagent could be reduced to a catalytic amount with the appropriate additives (Scheme 1).…”