Origins of the Endo and Exo Selectivities in Cyclopropenone, Iminocyclopropene, and Triafulvene Diels–Alder Cycloadditions

The endo and exo stereoselectivities of Diels–Alder reactions of cyclopropenone, iminocyclopropene, and substituted triafulvenes with butadiene were rationalized using density functional theory calculations. When cyclopropenone is the dienophile, there is a 1.8 kcal/mol preference for the exo cycloa...

Full description

Saved in:
Bibliographic Details
Published in:Journal of organic chemistry 2018-03, Vol.83 (6), p.3164-3170
Main Authors: Levandowski, Brian J, Hamlin, Trevor A, Helgeson, Roger C, Bickelhaupt, F. Matthias, Houk, K. N
Format: Article
Language:English
Subjects:
Cycloaddition Reaction
Cyclopentanes - chemical synthesis
Cyclopentanes - chemistry
Cyclopropanes - chemical synthesis
Cyclopropanes - chemistry
Models, Molecular
Molecular Conformation
Stereoisomerism
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The endo and exo stereoselectivities of Diels–Alder reactions of cyclopropenone, iminocyclopropene, and substituted triafulvenes with butadiene were rationalized using density functional theory calculations. When cyclopropenone is the dienophile, there is a 1.8 kcal/mol preference for the exo cycloaddition with butadiene, while the reaction of 3-difluoromethylene triafulvene with butadiene favors the endo cycloaddition by 2.8 kcal/mol. The influence of charge transfer and secondary orbital interactions on the stereoselectivity of Diels–Alder reactions involving triafulvenes and heteroanalogs is discussed. The predicted stereoselectivity correlates with both the charge and highest occupied molecular orbital (HOMO) coefficient at the C3 carbon of the triafulvene motif.
ISSN:0022-3263
1520-6904
DOI:10.1021/acs.joc.8b00025