Two complimentary routes to chiral dibenzazepinium halides have been developed. This has enabled the synthesis and evaluation of a range of potential phase-transfer catalysts (PTC) for asymmetric alkylation and Michael addition reactions involving glycine imine esters.
Asymmetric PTC Alkylation of Glycine Imines: Variation of the Imine Ester Moiety
作者:Barry Lygo、Bryan Allbutt
DOI:10.1055/s-2003-43368
日期:——
Studies into the enantioselective phase-transferalkylation of a series of glycine imine esters are presented. Using a quaternary ammonium salt catalyst derived from α-methylnaphthylamine, high enantioselectivities were obtained in reactions involving imines containing tert-butyl, benzhydryl, and benzyl esters. In contrast, a quaternary ammonium salt catalyst derived from dihydrocinchonidine gave highest
Directing the Cation Recognition Ability of Calix[4]arenes toward Asymmetric Phase-Transfer Catalysis
作者:Nicola Alessandro De Simone、Rosaria Schettini、Carmen Talotta、Carmine Gaeta、Irene Izzo、Giorgio Della Sala、Placido Neri
DOI:10.1002/ejoc.201700912
日期:2017.10.10
the first time in asymmetric phase-transfercatalysis. The binding affinities of a series of chiral α-methylbenzylamine-derived calix[4]arene-amides toward Na+ guest have been determined by 1H NMR spectroscopic titration experiments. The good apparent association constant values are consistent with the macrocycles' catalytic efficiency in the asymmetric alkylation reaction of N-(diphenylmethylene)glycine
A highly chemo- and enantioselective PTC alkylation has been developed that allows rapid access to orthogonally protected (S,S)-isodityrosine. Utility of this material in the construction of isodityrosine-containing cyclic peptides is demonstrated by synthesis of the natural product renieramide.