Selective Cross‐Coupling of Unsaturated Substrates on AlI

The AlI compound NacNacAl (1, NacNac = [ArNC(Me)CHC(Me)NAr]−, Ar = 2,6‐iPr2C6H3) serves as a template for the chemoselective coupling between carbonyls (benzophenone, fenchone, isophorone, p‐tolyl benzoate, N,N‐dimethylbenzamide, (1‐phenylethylidene)aniline) and pyridine. With the CH‐acidic ketone (...

Full description

Saved in:
Bibliographic Details
Published in:Chemistry : a European journal 2021-03, Vol.27 (18), p.5730-5736
Main Authors: Dmitrienko, Anton, Pilkington, Melanie, Nikonov, Georgii I.
Format: Article
Language:English
Subjects:
Adducts
aluminum
Aniline
Benzoates
Benzoic acid
Benzophenone
Camphor
Carbonyl compounds
Carbonyls
Chemistry
Coupling (molecular)
Cross coupling
Ketones
main group elements
pyridine
Pyridines
reductive coupling
Substrates
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The AlI compound NacNacAl (1, NacNac = [ArNC(Me)CHC(Me)NAr]−, Ar = 2,6‐iPr2C6H3) serves as a template for the chemoselective coupling between carbonyls (benzophenone, fenchone, isophorone, p‐tolyl benzoate, N,N‐dimethylbenzamide, (1‐phenylethylidene)aniline) and pyridine. With the CH‐acidic ketone (1R)‐(+) camphor, the reaction affords a hydrido alkoxide compound of Al, formed as the result of enolization, whereas an enolizable imine, (1‐phenylethylidene)aniline, and the bulky ketone isophorone, still chemoselectively couple with pyridine. In contrast, reaction with the ester p‐tolyl benzoate results in cleavage of the ester bond together with replacement of the alkoxy group by a hydrogen atom of the pyridine moiety. This study demonstrates that for carbonyl substrates featuring phenyl substituents, the reaction proceeds via intermediate formation of η2(C,X)‐coordinated (X = O, N) carbonyl adducts, whereas the reaction of 1 with (R)‐(−)‐fenchone in the absence of pyridine leads to CH activation in the pendant isopropyl group of the Ar substituent of the NacNac ligand. AlI compound NacNacAl mediates chemoselective cross‐coupling of carbonyl substrates (non‐enolizable ketones, imines, and esters) with pyridine.
ISSN:0947-6539
1521-3765
DOI:10.1002/chem.202004907