Organocatalyzed Phospha-Michael Addition: A Highly Efficient Synthesis of Customized Bis(acyl)phosphane Oxide Photoinitiators
Abstract
Addition of the P-H bond in bis(mesitoyl)phosphine, HP(COMes)(2) (BAPH), to a wide variety of activated carbon-carbon double bonds as acceptors was investigated. While this phospha-Michael addition does not proceed in the absence of an additive or catalyst, excellent results were obtained with stoichiometric basic potassium or caesium salts. Simple amine bases can be employed in catalytic amounts, and tetramethylguanidine (TMG) in particular is an outstanding catalyst that allows the preparation of bis(acyl)phosphines, R-P(COMes)(2), under very mild conditions in excellent yields after only a short time. All phosphines RP(COMes)(2) can subsequently be oxidized to the corresponding bis(acyl)phosphane oxides, RPO(COMes)(2), a substance class belonging to the most potent photoinitiators for radical polymerizations known to date. Thus, a simple and highly atom economic method has been found that allows the preparation of a broad range of photoinitiators adapted to their specific field of application even on a large scale. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000587905Publication status
publishedExternal links
Journal / series
Chemistry - A European JournalVolume
Pages / Article No.
Publisher
Wiley-VCHSubject
acylphosphane oxides; organocatalysis; phospha-Michael addition; photoinitiators; radical polymerizationOrganisational unit
03447 - Grützmacher, Hansjörg (emeritus) / Grützmacher, Hansjörg (emeritus)
03447 - Grützmacher, Hansjörg (emeritus) / Grützmacher, Hansjörg (emeritus)
Funding
ETH-46 21-1 - Lewis-acid promoted synthesis of primary and secondary phosphanes (ETHZ)
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