Highly Diastereo- and Enantioselective Reagents for Aldehyde Crotylation

Abstract

Two new, crystalline solid, storable, and highly enantioselective reagents for aldehyde crotylation have been developed. Both (cis and trans) crotylsilane reagents are easily prepared in bulk, require trivial reaction conditions, and provide the homoallylic alcohol products with near diastereo- and enantiospecificity in many cases.

Copper complexes bearing methylthiophenyl and methylfuranyl derivatives of (R,R)-1,2-diaminocyclohexane: X-ray structures and catalytic exploitation in Henry reaction

“…7 Despite the increased acidity of the N-H proton, 8 these C 2 -type symmetrical ligand precursors form stable metal complexes, creating chiral environments for catalytic reactions.…”

A More Comprehensive and Highly Practical Solution to Enantioselective Aldehyde Crotylation

“…6 While these characteristics go a long way towards realization of a more practical and user-friendly system, the reagents suffer from one highly significant limitation: the substrate scope is exceedingly narrow with aromatic, unsaturated, and sterically hindered aliphatic aldehydes all giving moderate to low yields, or even, in many cases, no product at all. For example, reagents 1 and 2 completely fail to react productively or at all with 3 , α-methylcinnamaldehyde, and 4 .…”

Origins of Stereoselectivity in Strain‐Release Allylations

“…Experimentally, the cis-crotyl version of the diazasilane reagent gives the syn product, and the trans-crotyl diazasilane reagent gives anti. [7] The calculations show that only the four transition states with apical aldehyde, TS1-TS4, are true saddle points (Figure 1). This places electronegative atoms, N and O, in Scheme 2.…”