Development of Non-<i>C</i>2-symmetric ProPhenol Ligands. The Asymmetric Vinylation of <i>N</i>-Boc Imines
作者:Barry M. Trost、Chao-I (Joey) Hung、Dennis C. Koester、Yan Miller
DOI:10.1021/acs.orglett.5b01755
日期:2015.8.7
The development and application of a newgeneration of non-C2-symmetric ProPhenol ligands is reported herein. Rational design of the ProPhenol ligand paved the way to the first catalytic and asymmetric vinylation of N-Boc imines via hydrozirconation giving rise to valuable allylic amines in excellent yields and enantioselectivities. The utility of this method was demonstrated by developing the shortest
Highly Enantioselective Titanium-Catalyzed Cyanation of Imines at Room Temperature
作者:Abdul Majeed Seayad、Balamurugan Ramalingam、Kazuhiko Yoshinaga、Takushi Nagata、Christina L. L. Chai
DOI:10.1021/ol902540h
日期:2010.1.15
A highly active and enantioselective titanium-catalyzed cyanation of imines at roomtemperature is described. The catalyst used is a partially hydrolyzed titanium alkoxide (PHTA) precatalyst together with a readily available N-salicyl-β-aminoalcohol ligand. Up to 98% ee was obtained with quantitative yields in 15 min of reaction time using 5 mol % of the catalyst. Various N-protecting groups such as
Asymmetric Synthesis of <i>anti</i>-β-Amino-α-Hydroxy Esters via Dynamic Kinetic Resolution of β-Amino-α-Keto Esters
作者:C. Guy Goodman、Dung T. Do、Jeffrey S. Johnson
DOI:10.1021/ol4009206
日期:2013.5.17
method for the asymmetricsynthesis of enantioenriched anti-α-hydroxy-β-amino acid derivatives by enantioconvergent reduction of the corresponding racemic α-keto esters is presented. The requisite α-keto esters are prepared via Mannich addition of ethyl diazoacetate to imines followed by oxidation of the diazo group with Oxone. Implementation of a recently developed dynamickinetic resolution of β-substituted-α-keto
Broad Spectrum Enolate Equivalent for Catalytic Chemo-, Diastereo-, and Enantioselective Addition to <i>N</i>-Boc Imines
作者:Barry M. Trost、Chao-I (Joey) Hung
DOI:10.1021/jacs.5b11248
日期:2015.12.23
Their susceptibility to other reactions such as Michael additions and the difficulty of controlling the enolate geometry make them difficult substrates. Mannich-type reactions, which previously have not been reported using N-carbamoyl-imines with simple ketone enolates, became our objective. In this report, we describe the first direct catalytic Mannich-type reaction between various ynones and N-Boc