An effective asymmetric α-phenylation of methylketones with triphenylaluminium in the presence of (+)-benzopyranoisoxazolidine has been developed. The reaction proceeds via the in situ formation of a chiral N-alkoxyenamine and the subsequent diastereoselective nucleophilic phenylation to provide α-phenylated products in moderate to good yields, with high enantioselectivities.
A stereoselectivehypervalent iodine-promoted oxidative rearrangement of 1,1-disubstituted alkenes has been developed. This practically simple protocol provides access to enantioenriched α-arylated ketones without the use of transition metals from readily accessible alkenes.
Enantioselective CuH-Catalyzed Hydroacylation Employing Unsaturated Carboxylic Acids as Aldehyde Surrogates
作者:Yujing Zhou、Jeffrey S. Bandar、Stephen L. Buchwald
DOI:10.1021/jacs.7b04937
日期:2017.6.21
(CuH)-catalyzed coupling of α,β-unsaturated carboxylic acids to aryl alkenes to access chiral α-aryl dialkyl ketones is reported. A variety of substrate substitution patterns, sensitive functional groups, and heterocycles are tolerated in this reaction, which significantly expands the range of accessible products compared with existing hydroacylation methodology. Although mechanistic studies are ongoing, we propose
BVMO-catalysed dynamic kinetic resolution of racemic benzyl ketones in the presence of anion exchange resins
作者:Cristina Rodríguez、Gonzalo de Gonzalo、Ana Rioz-Martínez、Daniel E. Torres Pazmiño、Marco W. Fraaije、Vicente Gotor
DOI:10.1039/b922693a
日期:——
fluorescens ACB was employed in the presence of a weak anion exchange resin to perform dynamic kinetic resolutions of racemic benzyl ketones with high conversions and good optical purities. Different parameters that affect to the efficiency of the enzymatic Baeyer–Villiger oxidation and racemisation were analyzed in order to optimize the activity and selectivity of the biocatalytic system.