Campus Units

Chemistry, Ames Laboratory

Document Type

Article

Publication Version

Accepted Manuscript

Publication Date

4-19-2021

Journal or Book Title

Chemistry–A European Journal

DOI

10.1002/chem.202101146

Abstract

Three‐coordinate Ph BOX Me2 ZnR ( Ph BOX Me2 = phenyl‐(4,4‐dimethyl‐oxazolinato; R = Me 2a , Et 2b ) catalyzes the dehydrocoupling of primary or secondary silanes and alcohols to give silyl ethers and hydrogen, with high turnover numbers (TON), up to 10 7 , under solvent‐free conditions. Primary and secondary silanes react with small, medium, and large alcohols to give varying degrees of substitution, from mono‐alkoxylation to tri‐alkoxylation, while tri‐substituted silanes do not react with MeOH under these conditions. The effect of coordinative unsaturation on the behavior of the Zn catalyst is revealed through a dramatic variation of both rate law and experimental rate constants, which depend on the concentrations of both the alcohol and silane reactants. That is, the catalyst adapts its mechanism access the most facile and efficient conversion. In particular, either alcohol or silane bind to the open coordination site on the Ph BOX Me2 ZnOR catalyst to form a Ph BOX Me2 ZnOR(HOR) complex under one set of conditions or an unprecedented σ‐adduct Ph BOX Me2 ZnOR(H–SiR' 3 ) under other conditions. Saturation kinetics provide evidence for the latter species, in support of the hypothesis that σ‐bond metathesis reactions, involving four‐centered electrocyclic 2σ‐2σ transition states, are preceded by σ‐adducts.

Comments

This is the peer-reviewed version of the following article: Patnaik, Smita, Uddhav Kanbur, Arkady Ellern, and Aaron David Sadow. "Hydrosilane σ‐Adduct Intermediates in an Adaptive Zinc‐Catalyzed Cross‐Dehydrocoupling of Si–H and O–H Bonds." Chemistry–A European Journal (2021), which has been published in final form at DOI: 10.1002/chem.202101146. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. Posted with permission.

Copyright Owner

Wiley‐VCH GmbH

Language

en

File Format

application/pdf

Available for download on Tuesday, April 19, 2022

Published Version

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