Reactivity of a Palladacyclic Complex: A Monodentate Carbonate Complex and the Remarkable Selectivity and Mechanism of a Neophyl Rearrangement

Authors

Ava Behnia, The University of Western Ontario
Mahmood A. Fard, The University of Western Ontario
Johanna M. Blacquiere, The University of Western OntarioFollow
Richard J. Puddephatt, The University of Western Ontario

Document Type

Article

Publication Date

12-26-2017

Journal

Organometallics

Volume

36

Issue

24

First Page

4759

Last Page

4769

URL with Digital Object Identifier

10.1021/acs.organomet.7b00631

Abstract

The ligand N(CH2-2-C5H4N)2(CH2CH2CH2OH), L1, reacted with [Pd(CH2CMe2C6H4)(COD)] to give a new fluxional "cycloneophyl" organopalladium complex [Pd(CH2CMe2C6H4)(κ2-L1)], 1, which on attempted recrystallization from THF gave the monodentate carbonate complex [Pd(CO3)(κ3-L1)], 2. Complex 2 was prepared in designed syntheses by reaction of [PdCl(κ3-L1)]+ with silver carbonate or by reaction of [Pd(OH)(κ3-L1)]+ with CO2. Complex 1 reacted with aqueous CO2 to give the cationic neophylpalladium complex [Pd(CH2CMe2C6H5)(κ3-L1)]+(HCO3)-, 6. Complex 6 reacts with hydrogen peroxide to give complex 2 with release of a mixture of organic products, the major one being 2-phenyl-2-butanol, PB. The formation of PB involves a neophyl rearrangement with the unprecedented preference for methyl over phenyl migration. A mechanistic basis for this unexpected reaction is proposed, involving β-carbon elimination at a palladium(IV) center.