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
Asymmetric phase-transfer catalysis was first applied to the synthesis of chiral N,S-acetals by using amino acid-based bifunctional thiourea-ammonium salt catalysts. The reaction could be performed on the gram scale to give up to 93% ee and 99% yield with a catalyst loading as low as 0.1 mol % within 5 min.
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
Organocatalytic Asymmetric Mannich Reaction of 3-Hydroxyoxindoles/3-Aminooxindoles with in Situ Generated <i>N</i>-Boc-Protected Aldimines for the Synthesis of Vicinal Oxindole–Diamines/Amino Alcohols
A highly efficient asymmetricMannichreaction of 3-monosubstituted 3-aminooxindoles/3-hydroxyoxindoles with in situ generated N-Boc-protected aldimines catalyzed by the chiral bifunctional thiourea–tertiary amine catalyst has been developed. Under mild reaction conditions, a series of structurally diverse vicinal oxindole–diamines/amino alcohols were smoothly obtained in moderate to high yields (up