Synlett 2019; 30(15): 1738-1764
DOI: 10.1055/s-0037-1611875
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© Georg Thieme Verlag Stuttgart · New York

Effects of Chiral Ligands on the Asymmetric Carbonyl-Ene Reaction

Atefeh Bakhtiari
,
Javad Safaei-Ghomi
Department of Organic Chemistry, Faculty of Chemistry, University of Kashan, Kashan, P.O. Box 87317-51167, Iran   eMail: safaei@kashanu.ac.ir
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The authors are grateful to the University of Kashan for supporting this work.
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Publikationsverlauf

Received: 03. April 2019

Accepted after revision: 06. Juni 2019

Publikationsdatum:
23. Juli 2019 (online)


Abstract

The carbonyl-ene reaction is one of the most well-known reactions for C–C bond formation. Based on frontier molecular orbitals (FMO), carbonyl-ene reactions occur between the highest occupied molecular orbital (HOMO) of the ene compound bearing an active hydrogen atom at the allylic center and the lowest unoccupied molecular orbital (LUMO) of the electron-deficient enophile, which is a carbonyl compound. A high activation barrier enforces the concerted ene reaction rather than a Diels–Alder reaction at high temperature. Employing a catalytic system can eliminate defects in the ene reaction, and chiral catalysts promote the reaction under mild conditions to produce optically active compounds. In this account, we highlight investigations on the effects of various classes of chiral ligands on intermolecular and intramolecular carbonyl-ene reactions.

1 Introduction

2 Biaryl-Type Chiral Ligands

3 C 1- and C 2-Symmetric Bis(oxazoline) Ligands

4 Schiff Base Ligands

5 N,N′-Dioxide Ligands

6 Conclusions