Affordable Access

deepdyve-link
Publisher Website

Nonstatistical dynamics in the thermal C2-C6/diels-alder cyclization of enyne-allenes: effect of topology.

Authors
  • Samanta, Debabrata
  • Rana, Anup
  • Schmittel, Michael
Type
Published Article
Journal
The Journal of Organic Chemistry
Publisher
American Chemical Society
Publication Date
Feb 20, 2015
Volume
80
Issue
4
Pages
2174–2181
Identifiers
DOI: 10.1021/jo502693b
PMID: 25647469
Source
Medline
License
Unknown

Abstract

The thermal C(2)-C(6) (Schmittel) cyclization of an enyne-allene with two aryl rings at the allene terminus experimentally leads to three formal Diels-Alder (DA) cycloaddition products, two of which (involving the dimethylamino phenyl unit) are shown to form in a nonstatistical process. DFT computations on the reaction paths reveal that the two aryl rings (Ph vs PhNMe2) do not interact in a dynamic manner as their minimum energy pathways (MEPs) are separated by a large barrier. The preferential formation of the more-hindered DA product 8 (ortho to the dimethylamino group) over the less-hindered product 9 (para to the dimethylamino group), despite the higher energy TS for 8, suggests the occurrence of nonstatistical dynamics in the cyclization onto the dimethylamino phenyl unit, though. Potential energy surface (PES) computations indicate that the large amount of nonstatistical dynamics (97%) arises from facile IRC dynamics (left picture) that is compared with the non-IRC dynamics of a related system (∼76%, right picture, J. Org. Chem. 2014, 79, 2368).

Report this publication

Statistics

Seen <100 times