Structural reorganization of (allyl-, benzyl-, and propargylsulfanyl)-substituted 2-aza-1,3,5-trienes in t-BuOK/THF/DMSO: access to rare functionalized 2-thiazolines
作者:Nina A. Nedolya、Ol’ga A. Tarasova、Alexander I. Albanov、Boris A. Trofimov
DOI:10.1016/j.tetlet.2014.03.015
日期:2014.4
Treatment of (allyl-, benzyl-, and propargylsulfanyl)-substituted 2-aza-1,3,5-trienes, which are readily accessible from lithiated methoxyallene, isopropyl isothiocyanate, and allyl, benzyl, or propargyl bromide, respectively, with t-BuOK in THF/DMSO resulted in the unexpected formation of 2-thiazoline derivatives along with seven-membered azaheterocycles [in the case of (allyl- and benzylsulfanyl)-substituted 2-aza-1,3,5-trienes]. An unprecedented structural reorganization of the azatrienes into 2-thiazolines presumably occurs via alpha-deprotonation of the substituents at the sulfur atom followed by intramolecular [1,5]-cyclization. Deprotonation of the ketimine fragment of the same molecule followed by [1,71-electrocyclization resulted in azepine ring formation. (C) 2014 Elsevier Ltd. All rights reserved.