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Palladium-mediated CO2 extrusion followed by insertion of allenes: translating mechanistic studies to develop a one-pot method for the synthesis of alkenes

Citation

Yang, Y and Spyrou, B and White, JM and Canty, AJ and Donnelly, PS and O'Hair, RAJ, Palladium-mediated CO2 extrusion followed by insertion of allenes: translating mechanistic studies to develop a one-pot method for the synthesis of alkenes, Organometallics, 41 pp. 1595-1608. ISSN 0276-7333 (2022) [Refereed Article]

Copyright Statement

Copyright 2022 American Chemical Society

DOI: doi:10.1021/acs.organomet.2c00005

Abstract

A palladium-mediated one-pot synthesis of alkenes from aromatic carboxylic acids and allene substrates (R1R2C═C═CH2, where either: R1 = Ph, R2 = H; R1 = Ph, R2 = Me or R1 = nPe, R2 = H) is reported. This is an iso-electronic variant of CO2 extrusion–insertion (ExIn) reactions previously developed using heterocumulenes for the synthesis of thioamides (from isothiocyanates, RNCS), amidines (from carbodiimides, RNCNR), and amides (from isocyanates, RNCO). Evidence that the key aryl-palladium intermediate reacts to form a stable allyl-palladium product via insertion of the allene at the C2 position that enables the synthesis of alkenes was provided by a combination of gas-phase multistage mass spectrometry (MSn) experiments and condensed-phase monitoring using 1H NMR spectroscopy as well as theoretical computational data. Isolation and X-ray crystallographic analysis of the salt [(phen)Pd(CH2CH(Ar)CHPh)]+(CF3CO2) (where Ar = 2,6-dimethoxyphenyl) confirmed insertion of the allene at the C2 position and revealed a syn relationship between the two aryl groups. A survey of different hydrogen sources to promote the removal of palladium from the alkene product revealed that NaBH4 provides the highest yield and with the Z-alkene as the major isomer.

Item Details

Item Type:Refereed Article
Research Division:Chemical Sciences
Research Group:Inorganic chemistry
Research Field:Transition metal chemistry
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the chemical sciences
UTAS Author:Canty, AJ (Professor Allan Canty)
ID Code:151103
Year Published:2022
Deposited By:Chemistry
Deposited On:2022-07-19
Last Modified:2022-08-02
Downloads:0

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