Azine-N-oxides as effective controlling groups for Rh-catalysed intermolecular alkyne hydroacylation

Abstract

Heterocycle-derived aldehydes are challenging substrates in metal-catalysed hydroacylation chemistry. We show that by using azine N-oxide substituted aldehydes, good reactivity can be achieved, and that they are highly effective substrates for the intermolecular hydroacylation of alkynes. Employing a Rh(I)-catalyst, we achieve a mild and scalable aldehyde C–H activation, that permits the coupling with unactivated terminal alkynes, in good yields and with high regioselectivities (up to >20 : 1 l:b). Both substrates can tolerate a broad variety of functional groups. The reaction can also be applied to diazine aldehydes that contain a free N-lone pair. We demonstrate conversion of the hydroacylation products to the corresponding azine, through a one-pot hydroacylation/deoxygenation sequence. A one-pot hydroacylation/cyclisation, using N-Boc propargylamine, additionally leads to the synthesis of a bidentate pyrrolyl ligand.

Graphical abstract: Azine-N-oxides as effective controlling groups for Rh-catalysed intermolecular alkyne hydroacylation

Supplementary files

Article information

Article type
Edge Article
Submitted
17 Jul 2021
Accepted
07 Sep 2021
First published
14 Sep 2021
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., 2021, Advance Article

Azine-N-oxides as effective controlling groups for Rh-catalysed intermolecular alkyne hydroacylation

D. F. Moseley, J. Kalepu and M. C. Willis, Chem. Sci., 2021, Advance Article , DOI: 10.1039/D1SC03915F

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