Solid state conformations of α, β-unsaturated hydroxamates derived from the 'chiral Weinreb amide' auxiliary (S)-N-1-(1′-naphthyl)ethyl-O-tert-butylhydroxylamine. Issue 10 (15th October 2017)

• Record Type: Journal Article
• Authors: Davies, Stephen G.; Lee, James A.; Roberts, Paul M.; Thomson, James E.; Yin, Jingda
• Is Part Of: Tetrahedron, asymmetry. Volume 28:Issue 10(2017)
• Page Start: 1337
• Page End: 1341
• Publication Date: 2017-10-15
• Subjects: Asymmetry (Chemistry) -- Periodicals; 547.005
• DOI: 10.1016/j.tetasy.2017.07.009
• Languages: English
• ISSNs: 0957-4166

Abstract

Graphical abstract: Abstract: α, β-Unsaturated hydroxamates derived from the 'chiral Weinreb amide' auxiliary ( S )- N -1-(1′-naphthyl)ethyl- O - tert -butylhydroxylamine consistently adopt a defined conformation and undergo highly diastereoselective conjugate addition reactions with lithium amide reagents. The configuration of the N -1-(1′-naphthyl)ethyl group dictates the position of the O - tert -butyl group and also the configuration adopted by the pyramidal nitrogen atom via a 'chiral relay' effect. Conjugate addition of lithium amide reagents to these substrates proceeds on the face opposite to both the O - tert -butyl group and nitrogen lone-pair with high levels of diastereoselectivity. Abstract : ( S )- N - tert -Butoxy- N -1″-(1‴-naphthyl)ethyl ( E )-3-(2′-bromophenyl)propenamide: C25 H26 BrNO2 [ α ]D 25 = −56.9 ( c 1.0, CHCl3 ) Source of chirality: asymmetric synthesis Absolute configuration: ( S, E ) Abstract : ( S )- N - tert -Butoxy- N -1″-(1‴-naphthyl)ethyl ( E )-3-(3′-bromophenyl)propenamide: C25 H26 BrNO2 [ α ]D 25 = −26.9 ( c 1.0, CHCl3 ) Source of chirality: asymmetric synthesis Absolute configuration: ( S, E ) Abstract : ( S )- N - tert -Butoxy- N -1″-(1‴-naphthyl)ethyl ( E )-3-(4′-bromophenyl)propenamide: C25 H26 BrNO2 [ α ]D 25 = −17.2 ( c 0.5, CHCl3 ) Source of chirality: asymmetric synthesis Absolute configuration: ( S, E )