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Base‐Catalyzed Hydrosilylation of Ketones and Esters and Insight into the Mechanism
Author(s) -
Revunova Kseniya,
Nikonov Georgii I.
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201302728
Subject(s) - silanes , hydrosilylation , silane , ketone , chemistry , aldehyde , reagent , catalysis , organic chemistry
Simple bases (KO t Bu, KOH) catalyze the silane‐promoted reduction of ketones and esters to alcohols and of aldimines to amines. The inexpensive silane PMHS (polymethylhydrosiloxane) can be used as the reducing reagent. Double and triple bonds, as well as nitro‐ and cyano‐groups are tolerated. Careful dosing of the silane allows for chemoselective reduction of a more reactive group in the presence of a less reactive group (for example, aldehyde reduction in the presence of ketone/ketone reduction in the presence of ester group). Mechanistic studies showed that addition of base to silanes leads to silicate species, which are the acting reducing agents. Under basic conditions, hydrosiloxanes (tetramethyldisiloxane, TMDS; PMHS) convert into simple silanes (H 2 SiMe 2 , H 3 SiMe), making this a practical method to generate these challenging silanes.