Michael addition of nitroalkanes to nonactivated α,β-unsaturated δ-thiolactams: reactivity, diastereoselectivity, and comparison to α,β-unsaturated δ-lactams
作者:Jacek G. Sośnicki
DOI:10.1016/j.tet.2008.12.037
日期:2009.2
Aliphatic nitrocompounds add to nonactivated α,β-unsaturatedδ-thiolactams leading to 4-nitroalkyl functionalized δ-thiolactams in good yields. The addition is a stereocontrolled process with respect to substituents at C-6, and takes place producing trans 4,6-disubstituted adducts in most cases. Ease of the addition has been studied in relation to the structure of the δ-thiolactam acceptors, within
A novel chlorolactamization reaction of homoallylicamines has been developed. The treatment of homoallylicamines with dimethylzinc in chloroform led to the formation of the corresponding β-chlorolactams via the Prins-type cyclization of a carbamoyl chloride intermediate. The results of this study highlight the synthetic utility of chloroform as a source of both carbonyl group and chloride anion.
Two types of aminocarbonylation reaction of homoallylic amines have been developed. The treatment of homoallylic amines with triphosgene in dichloromethane led to formation of the corresponding beta-chlorolactams via Prins-type cyclization of a carbamoyl chloride intermediate. For the reaction in acetonitrile, beta-aminolactams were obtained via sequential Prins-type cyclization and Ritter-type reactions.