On the scope of the Pt-catalyzed Srebnik diborylation of diazoalkanes. An efficient approach to chiral tertiary boronic esters and alcohols via B-stabilized carbanions
作者:Andrew J. Wommack、Jason S. Kingsbury
DOI:10.1016/j.tetlet.2014.03.135
日期:2014.5
Conditions milder than those previously reported are shown to be generally applicable to the Pt-catalyzed insertion of non-carbonyl-stabilized diazoalkanes into B(2)pin(2). Selective transformation of one (pinacolato)boryl unit in the products is enabled by rapid, low-temperature deboronation in the presence of a Lewis base and genesis of a highly reactive B-stabilized carbanion. (C) 2014 Published by Elsevier Ltd.
Catalytic Asymmetric Formal Insertion of Aryldiazoalkanes into the C–H Bond of Aldehydes: Synthesis of Enantioenriched Acyclic α-Tertiary Aryl Ketones
A novel, catalytic enantioselective route to synthesize a variety of a-tertiary aryl ketones via a boron Lewis acid promoted formal insertion of aryldiazoalkane into the C-H bond of both aromatic and aliphatic aldehydes is described. In the presence of chiral (S)-oxazaborolidinium ion catalyst 1, the reaction proceeded in good yields (up to 94%) with excellent enantioselectivities (up to 99% ee).