The development of catalysts based on earth abundant metals in place of noble metals is becoming a central topic of catalysis. We herein report a cobalt/tetraphosphine complex catalyzed homogeneous hydrogenation of polar unsaturated compounds using an air- and moisture-stable and scalable precatalyst. By activation with potassium hydroxide, this cobalt system shows both high efficiency (up to 24000
CATALYST FOR ASYMMETRIC HYDROGENATION AND METHOD FOR MANUFACTURING OPTICALLY ACTIVE CARBONYL COMPOUND USING THE SAME
申请人:YAMADA Shinya
公开号:US20120136176A1
公开(公告)日:2012-05-31
The present invention provides a catalyst used for manufacturing an optically active carbonyl compound by selective asymmetric hydrogenation of an α,β-unsaturated carbonyl compound, which is insoluble in a reaction mixture, and a method for manufacturing the corresponding optically active carbonyl compound. Particularly, the invention provides a catalyst for obtaining an optically active citronellal useful as a flavor or fragrance, by selective asymmetric hydrogenation of citral, geranial or neral. The invention relates to a catalyst for asymmetric hydrogenation of an α,β-unsaturated carbonyl compound, which comprises: a powder of at least one metal selected from metals belonging to Group 8 to Group 10 of the Periodic Table, or a metal-supported substance in which the at least one metal is supported on a support; an optically active peptide compound; and an acid, and also relates to a method for manufacturing an optically active carbonyl compound using the same.
The synthesis of non-racemic β-alkyl-β-aryl-disubstituted allyl alcohols and their transformation into allylamines and amino acids bearing a quaternary stereocenter
synthesis of non-racemic β-alkyl-β-aryl allyl alcohols and their transformation into allylamines bearing a quaternary stereogenic center is reported. The allyl alcohols were prepared either by Cu-catalyzed enantioselective reduction of enones or by sequential alkylation/hydrostannylation/Stille coupling of non-racemic propargyl alcohols. The prepared β-alkyl-β-aryl allyl alcohols were converted (after carbamoylation)
Alcohol Dehydrogenases and N‐Heterocyclic Carbene Gold(I) Catalysts: Design of a Chemoenzymatic Cascade towards Optically Active β,β‐Disubstituted Allylic Alcohols
combination of gold(I) and enzyme catalysis is used in a two-step approach, including Meyer–Schuster rearrangement of a series of readily available propargylicalcohols followed by stereoselective bioreduction of the corresponding allylic ketone intermediates, to provide optically pure β,β-disubstituted allylic alcohols. This cascade involves a gold N-heterocycliccarbene and an enzyme, demonstrating the
Acyclic quaternary centers from asymmetric conjugate addition of alkylzirconium reagents to linear trisubstituted enones
作者:Zhenbo Gao、Stephen P. Fletcher
DOI:10.1039/c6sc02811j
日期:——
Synthetic methods for the selective formation of all carbon quaternary centres in non-cyclic systems are rare. Here we report highly enantioselective Cu-catalytic asymmetric conjugate addition of alkylzirconium species to twelve...