Multiple Cycloaddition Reactions of Ketones with a β-Diketiminate Al Compound.

Abstract

A β-diketiminate Al compound (1) with an exocyclic double bond reacts with two equivalents each of benzophenone and 2-benzoylpyridine in a [4+2] cycloaddition to generate bicyclic and tricyclic compounds 2 and 3, respectively. Compound 2 consists of six- and eight-membered aluminium rings, whereas 3 has two five- and one eight-membered ring. Compounds 2 and 3 were characterized by a number of analytical tools including single-crystal X-ray diffraction. The quantum mechanical calculations suggest that the dissociation of the solvent molecule from 1 would lead to an active species 1A having two 1,4-dipolar 4π electron moieties, in which the electrophilic site is the Al atom and the nucleophilic positions are polarized exocyclic and endocyclic C=C π bonds. The detailed mechanistic study shows that the dipolarophiles, benzophenone, and 2-benzoylpyridine undergo double cycloaddition with two 1,4-dipolar 4π electron moieties of 1A. Herein, the addition of one molecule of the dipolarophile promotes the addition of the second one.

DOI: 10.1002/chem.201503137

Cite this paper

@article{Sarish2015MultipleCR, title={Multiple Cycloaddition Reactions of Ketones with a β-Diketiminate Al Compound.}, author={Sankaranarayana Pillai Sarish and Prinson P. Samuel and Herbert W Roesky and Carola Schulzke and Karikkeeriyil Nijesh and Susmita De and Pattiyil Parameswaran}, journal={Chemistry}, year={2015}, volume={21 52}, pages={19041-7} }