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Interconverting Lanthanum Hydride and Borohydride Catalysts for C=O Reduction and C−O Bond Cleavage
Author(s) -
Patnaik Smita,
Sadow Aaron D.
Publication year - 2019
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201813305
Subject(s) - hydroboration , chemistry , hydride , lanthanum , diborane , catalysis , medicinal chemistry , bond cleavage , borohydride , cleavage (geology) , alkyl , protonolysis , organic chemistry , boron , metal , geotechnical engineering , fracture (geology) , engineering
The high catalytic reactivity of homoleptic tris(alkyl) lanthanum La{C(SiHMe 2 ) 3 } 3 is highlighted by C−O bond cleavage in the hydroboration of esters and epoxides at room temperature. The catalytic hydroboration tolerates functionality typically susceptible to insertion, reduction, or cleavage reactions. Turnover numbers (TON) up to 10 000 are observed for aliphatic esters. Lanthanum hydrides, generated by reactions with pinacolborane, are competent for reduction of ketones but are inert toward esters. Instead, catalytic reduction of esters requires activation of the lanthanum hydride by pinacolborane.