Issue 30, 2016

Temperature-dependent annuloselectivity and stereochemistry in the reactions of methanesulfonyl sulfene with imines

Abstract

The annuloselectivity in the reactions of methanesulfonyl sulfene and imines varies with temperature. At a relatively higher temperature of 20 °C, the [2s + 2i] annulation of different N-alkyl imines occurs exclusively, giving four-membered trans-β-sultams in up to 69% yields. At a lower temperature of −78 °C, the [2s + 2i + 2i] annulation of N-methyl imines takes place specifically, delivering six-membered 1,2,4-thiadiazine 1,1-dioxides, 4-aza-δ-sultams, in up to 80% yields, with diverse configurations at the C3, C5, and C6 stereocenters. The trans-stereochemistry involved in the [2s + 2i] annulations is attributed to the conrotatory ring closure of the thermodynamically stable 2,3-thiazabutadiene-type zwitterionic intermediates, while the diverse stereochemical outcomes in the [2s + 2i + 2i] annulations are caused by the iminium isomerization in the stepwise nucleophilic [4 + 2] annulation between the same zwitterionic intermediates and a second molecule of N-methyl imines.

Graphical abstract: Temperature-dependent annuloselectivity and stereochemistry in the reactions of methanesulfonyl sulfene with imines

Supplementary files

Article information

Article type
Paper
Submitted
09 Jun 2016
Accepted
01 Jul 2016
First published
04 Jul 2016

Org. Biomol. Chem., 2016,14, 7258-7267

Temperature-dependent annuloselectivity and stereochemistry in the reactions of methanesulfonyl sulfene with imines

Q. Wu, Z. Yang and J. Xu, Org. Biomol. Chem., 2016, 14, 7258 DOI: 10.1039/C6OB01259K

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements