Diplumbane-catalysed solvent- and additive-free hydroboration of ketones and aldehydes

Zhang, Guoqi; Li, Sihan; Zeng, Haisu; Zheng, Shengping; Neary, Michelle C.

doi:10.1039/d2ra03731a

Cited by 5 publications

(1 citation statement)

References 46 publications

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“…The hydroboration mechanism for (pre)catalysts A-J is believed to involve the insertion of the carbonyl substrate into a Group 14 elementhydride bond. Catalysts A, [6] B, [7] and C [8] feature hydride ligands, while for catalysts D-J, exchange of a siloxide (D), [9] chloride (E [10] and F [11]), chalcogenide (E), [12] tris(trimethylsilyl)silyl (G), [13] triflate (H [14] and I [15]), or neosilyl (J) [16] ligand to generate a hydride is proposed. Scheme 1.…”

Section: Introductionmentioning

confidence: 99%

Group 14 Metallocene Catalysts for Carbonyl Hydroboration and Cyanosilylation

Robertson,

Fujiwara,

Liberman-Martin

2023

Preprint

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A series of six Group 14 metallocene compounds (M = Ge, Sn, Pb) were studied as catalysts for carbonyl hydroboration and cyanosilylation reactions at room temperature. Both bis(pentamethylcyclopentadienyl) and tetramethyldisiloxa[3]metallocenophane compounds were compared. The tin and lead metallocenophanes exhibited the highest reactivity in hydroboration and cyanosilylation reactions. Hammett analysis of aldehyde hydroboration provided a rho value of 0.73, suggesting a buildup of negative charge during the turnover-limiting step, consistent with the transition state for hydride transfer to the carbonyl center. NMR studies of Lewis acidity indicate that the Ge, Sn, and Pb tetramethyldisiloxa[3]metallocenophane compounds are weak Lewis acids.

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