Škoch K, Daniliuc CG, Kehr G, Erker G. Alkyne 1,1-Hydroboration to a Reactive Frustrated P/B-H Lewis Pair.
Angew Chem Int Ed Engl 2021;
60:6757-6763. [PMID:
33306863 DOI:
10.1002/anie.202014562]
[Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Indexed: 12/18/2022]
Abstract
The Mes2 P-C≡C-SiMe3 alkyne reacts with the borane H2 B-Fmes by means of a rare 1,1-hydroboration reaction to give an unsaturated C2 -bridged frustrated P/B-H Lewis pair. Most of its reactions are determined by the presence of the B-H functionality at the FLP function and the activated connecting carbon-carbon double bond. It reduces carbon monoxide to the formyl stage. With nitriles it reacts in an extraordinary way: it undergoes a reaction sequence that eventually results in the formation of a P-substituted dihydro-1,2-azaborole derivative. Several similar examples were found. In one case a P-ylide was isolated that was related to an intermediate of the reaction sequence. It subsequently opened in an alternative way to give an alkenyl borane product.
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