Bi(III) Catalysed O-acylative cleavage of 2,5-dimethyltetrahydrofuran: A substrate dependent borderline mechanism

Costello, James F.; Draffin, William N.; Paver, Simon P.

Abstract

The Bi(III) catalysed O-acylative cleavage of cis- and trans-2,5- dimethyltetrahydrofuran 4 with AcCl, BzCl or i-PrCOCl is stereochemically consistent with the operation of a concerted process (AND N), which proceeds via a stabilised carbocation or 'loose' S N2 transition state. However, the O-acylative cleavage of cis-2,5-dimethyltetrahydrofuran 4 with sterically demanding electrophiles such as t-BuCOCl, appears to be stereochemically consistent with the alternative SN1 (DN+AN) pathway. The apparent merging of mechanistic pathways is rationalised by the participation of a strained acyloxy cation. © 2005 Elsevier Ltd. All rights reserved.

• Journal Article Type: Article
• Publication Date: Jul 11, 2005
• Journal: Tetrahedron
• Print ISSN: 0040-4020
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 61
• Issue: 28
• Pages: 6715-6719
• DOI: https://doi.org/10.1016/j.tet.2005.05.014
• Keywords: O-acylative cleavage, dimethyltetrahydrofuran, substrate dependent, borderline mechanism
• Public URL: https://uwe-repository.worktribe.com/output/1048634
• Publisher URL: http://dx.doi.org/10.1016/j.tet.2005.05.014