Tailoring Reaction Selectivity by Modulating a Catalytic Diad on a Foldamer Scaffold
作者:Mary Katherine Andrews、Xinyu Liu、Samuel H. Gellman
DOI:10.1021/jacs.1c11542
日期:2022.2.9
of a tunable molecular scaffold to align a reactive diad for bifunctional catalysis can reveal relationships between functional group identity and reactivity that might otherwise be impossible to identify. Here we use an α/β-peptide helix to show that an aligned pair of primary amine groups is uniquely competent to catalyze crossed aldol condensations with an aryl aldehyde as the electrophile. Geometrically
The reaction of an acyltrimethylsilane enolate with 2 eq of an aldehyde gives a 1:2 adduct, while that with the enolate of an α-chloroacyltrimethylsilane affords an α, β-unsaturated aldehyde as a 1:1 adduct accompanied by the carboxylic acid derived from the starting aldehyde. An oxidation-reductionreaction mechanism on the trimethylsilylcarbonyl group has been proposed.