Issue 30, 2020

Ring-opening carbonyl–olefin metathesis of norbornenes

Abstract

A computational and experimental study of the hydrazine-catalyzed ring-opening carbonyl–olefin metathesis of norbornenes is described. Detailed theoretical investigation of the energetic landscape for the full reaction pathway with six different hydrazines revealed several crucial aspects for the design of next-generation hydrazine catalysts. This study indicated that a [2.2.2]-bicyclic hydrazine should offer substantially increased reactivity versus the previously reported [2.2.1]-hydrazine due to a lowered activation barrier for the rate-determining cycloreversion step, a prediction which was verified experimentally. Optimized conditions for both cycloaddition and cycloreversion steps were identified, and a brief substrate scope study for each was conducted. A complication for catalysis was found to be the slow hydrolysis of the ring-opened hydrazonium intermediates, which were shown to suffer from a competitive and irreversible cycloaddition with a second equivalent of norbornene. This problem was overcome by the strategic incorporation of a bridgehead methyl group on the norbornene ring, leading to the first demonstrated catalytic carbonyl–olefin metathesis of norbornene rings.

Graphical abstract: Ring-opening carbonyl–olefin metathesis of norbornenes

Supplementary files

Article information

Article type
Edge Article
Submitted
20 Apr 2020
Accepted
30 Jun 2020
First published
01 Jul 2020
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2020,11, 7884-7895

Ring-opening carbonyl–olefin metathesis of norbornenes

J. Jermaks, P. K. Quach, Z. M. Seibel, J. Pomarole and T. H. Lambert, Chem. Sci., 2020, 11, 7884 DOI: 10.1039/D0SC02243H

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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