Issue 12, 2017

Rhodium-catalyzed asymmetric 1,4-addition reactions of aryl boronic acids with nitroalkenes: reaction mechanism and development of homogeneous and heterogeneous catalysts

Abstract

Asymmetric 1,4-addition reactions with nitroalkenes are valuable because the resulting chiral nitro compounds can be converted into various useful species often used as chiral building blocks in drug and natural product synthesis. In the present work, asymmetric 1,4-addition reactions of arylboronic acids with nitroalkenes catalyzed by a rhodium complex with a chiral diene bearing a tertiary butyl amide moiety were developed. Just 0.1 mol% of the chiral rhodium complex could catalyze the reactions and give the desired products in high yields with excellent enantioselectivities. The homogeneous catalyst thus developed could be converted to a reusable heterogeneous metal nanoparticle system using the same chiral ligand as a modifier, which was immobilized using a polystyrene-derived polymer with cross-linking moieties, maintaining the same level of enantioselectivity. To our knowledge, this is the first example of asymmetric 1,4-addition reactions of arylboronic acids with nitroalkenes in a heterogeneous system. Wide substrate generality and high catalytic turnover were achieved in the presence of sufficient water without any additives such as KOH or KHF2 in both homogeneous and heterogeneous systems. Various insights relating to a rate-limiting step in the catalytic cycle, the importance of water, role of the secondary amide moiety in the ligand, and active species in the heterogeneous system were obtained through mechanistic studies.

Graphical abstract: Rhodium-catalyzed asymmetric 1,4-addition reactions of aryl boronic acids with nitroalkenes: reaction mechanism and development of homogeneous and heterogeneous catalysts

Supplementary files

Article information

Article type
Edge Article
Submitted
10 Jul 2017
Accepted
10 Oct 2017
First published
11 Oct 2017
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., 2017,8, 8362-8372

Rhodium-catalyzed asymmetric 1,4-addition reactions of aryl boronic acids with nitroalkenes: reaction mechanism and development of homogeneous and heterogeneous catalysts

H. Miyamura, K. Nishino, T. Yasukawa and S. Kobayashi, Chem. Sci., 2017, 8, 8362 DOI: 10.1039/C7SC03025H

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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