Si-free enolate Claisen rearrangements of enamido substrates

Abstract

α-Alkyl β-amino esters are available in high diastereoselectivity through a silicon-free Claisen enolate [3,3]-sigmatropic rearrangement of enamide esters. Optimisation studies have probed the crucial role of the initial enolisation and the nature of the enamide N-centre. The demonstration of chirality transfer and the formation of β-proline systems, is also presented.

Organoselenium-Catalyzed, Hydroxy-Controlled Regio- and Stereoselective Amination of Terminal Alkenes: Efficient Synthesis of 3-Amino Allylic Alcohols

“…3-Amino allylic alcohols are versatile synthetic intermediates and could be conveniently converted to β-amino acids, hydroxy carboxylic acids, 1,2-amino alcohols, 1,3-amino alcohols and amino cyclopropyl carbinols by known methods. In general, they are prepared in multiple steps with alkynes as starting materials via ynamide intermediates. , However, multistep manipulations and the utility of alkyne substrates have limited their broad applications in synthesis. Alternatively, allylic alcohol could serve as substrate to afford 3-amino allylic alcohol in several steps involving OH protection, hydroxylation via borylation, and then oxidation followed by amination .…”

“…Satisfyingly, when the tertiary allylic alcohols, i.e., 1,1-aryl, alkyl or 1,1-alkyl, alkyl-substituted allylic alcohols, were utilized as the substrates, the desired products were formed in good yields as well ( 2m – 2p ) despite the bulky quaternary carbon connects to the double bond. In contrast, 3-amino tertiary allylic alcohols could not be accessed by the known methods. − …”