The Catalytic Asymmetric Mukaiyama-Michael Reaction of Silyl Ketene Acetals with α,β-Unsaturated Methyl Esters
نویسندگان
چکیده
منابع مشابه
Gallium tribromide catalyzed coupling reaction of alkenyl ethers with ketene silyl acetals.
متن کامل
Development of a general, enantioselective organocatalytic Mukaiyama-Michael reaction with α,β-unsaturated aldehydes.
LUMO-lowering organocatalysis has been extended to promote the conjugate addition of S-alkyl and -pyrrolyl silylketene acetals to α,β-unsaturated aldehydes, yielding both, syn and anti Mukaiyama-Michael products with high levels of enantioselectivity. This strategy allows for the generation of chemically useful 1,5-dicarbonyl systems and again highlights the utility of organocatalysis.
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The enantioselective vinylogous Michael reaction of vinylketene silyl N,O-acetals derived from α,β-unsaturated N-acyl pyrroles and a broad range of α,β-unsaturated aldehydes proceeds with good regio-, diastereo-, and enantioselectivity when the Hayashi-Jørgensen diphenylprolinolsilylether was employed as a chiral organocatalyst. Products were obtained in generally good yields and as single ster...
متن کاملA concise synthesis of tubuphenylalanine and epi-tubuphenylalanine via a diastereoselective Mukaiyama aldol reaction of silyl ketene acetal.
We have developed a straightforward and auxiliary-free synthetic route towards tBu-tubuphenylalanine (tBu-Tup) and tBu-epi-tubuphenylalanine (tBu-epi-Tup), which are the key components of tubulysins and their analogs. A Lewis acid-mediated diastereoselective Mukaiyama aldol reaction using silyl ketene acetal and N-Boc-L-phenylalaninal provided γ-amino-β-hydroxyl-α-methyl esters, which were deox...
متن کاملEnantioselective acylation of silyl ketene acetals through fluoride anion-binding catalysis.
A highly enantioselective acylation of silyl ketene acetals with acyl fluorides has been developed to generate useful α,α-disubstituted butyrolactone products. This transformation is promoted by a new thiourea catalyst and 4-pyrrolidinopyridine and represents the first example of enantioselective thiourea anion-binding catalysis with fluoride.
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ژورنال
عنوان ژورنال: Angewandte Chemie International Edition
سال: 2018
ISSN: 1433-7851
DOI: 10.1002/anie.201712088