83947-56-2Relevant articles and documents
Synthesis of tri-substituted vinyl boronates via ruthenium-catalyzed olefin cross-metathesis
Morrill, Christie,Funk, Timothy W.,Grubbs, Robert H.
, p. 7733 - 7736 (2004)
Tri-substituted vinyl pinacol boronates are synthesized using cross-metathesis of α-substituted vinyl boronates. The reactions proceed with moderate yields and high Z-selectivity when R1 = methyl. When R1 is larger than a methyl group, yields and Z-selectivity are moderate at best, and the reactions are highly substrate dependent.
(Z)-Selective Hydroboration of Terminal Alkynes Catalyzed by a PSP-Pincer Rhodium Complex
Lyu, Yanzong,Toriumi, Naoyuki,Iwasawa, Nobuharu
supporting information, p. 9262 - 9266 (2021/11/30)
A highly (Z)-selective hydroboration of terminal alkynes was achieved using a thioxanthene-based PSP-pincer rhodium catalyst. This hydroboration exhibited good chemoselectivity toward alkynes over carbonyl compounds such as ketones and aldehydes. The mechanistic studies indicated the involvement of rhodium-vinylidene intermediates, and the high (Z)-selectivity could be attributed to the rigid and electron-rich nature of the PSP-rhodium catalyst.
Tropylium-Promoted Hydroboration Reactions: Mechanistic Insights Via Experimental and Computational Studies
Mai, Binh Khanh,Nguyen, Thanh Vinh,Ton, Nhan N. H.
supporting information, p. 9117 - 9133 (2021/07/19)
Hydroboration reaction of alkynes is one of the most synthetically powerful tools to access organoboron compounds, versatile precursors for cross-coupling chemistry. This type of reaction has traditionally been mediated by transition-metal or main group catalysts. Herein, we report a novel method using tropylium salts, typically known as organic oxidants and Lewis acids, to promote the hydroboration reaction of alkynes. A broad range of vinylboranes can be easily accessed via this metal-free protocol. Similar hydroboration reactions of alkenes and epoxides can also be efficiently catalyzed by the same tropylium catalysts. Experimental studies and DFT calculations suggested that the reaction follows an uncommon mechanistic pathway, which is triggered by the hydride abstraction of pinacolborane with tropylium ion. This is followed by a series ofin situcounterion-activated substituent exchanges to generate boron intermediates that promote the hydroboration reaction.