Copper‐Catalyzed Asymmetric 1,4‐Hydroboration of Coumarins with Pinacolborane: Asymmetric Synthesis of Dihydrocoumarins
作者:Hyohyun Kim、Jaesook Yun
DOI:10.1002/adsc.201000310
日期:2010.10.9
An efficient asymmetric addition of pinacolborane to 4-substituted coumarins proceeded with high enantioselectivity in the presence of a copper(I)-QuinoxP complex as a catalyst to produce the corresponding 1,4-hydroboration products. Treatment of the intermediates with electrophiles, without isolation, resulted in enantioenriched dihydrocoumarins. The utility of this protocol was demonstrated in the
Catalytic Asymmetric Cyclocarbonylation of <i>o</i>-Isopropenylphenols: Enantioselective Synthesis of Six-Membered Ring Lactones
作者:Chune Dong、Howard Alper
DOI:10.1021/jo040109f
日期:2004.7.1
Cyclocarbonylation of o-isopropenylphenols with CO (500 psi) and H2 (100 psi), using Pd(OAc)2 and (+)-DIOP as the chiral catalyst, in CH2Cl2 affords 3,4-dihydro-4-methylcoumarins in 60−85% yield and in up to 90% enantiomeric excess. The stereoselectivity is influenced by the structure of the chiral phosphine ligands and substrates, as well as by the reaction conditions.
A highly efficient enantioselective [1,3] O-to-C rearrangement of racemic vinyl ethers that operates under mild conditions was developed. This method with chiral ferrous complex catalyst provided an efficient access to a wide range of chromanols with high yields and excellent enantioselectivities. In addition, an important urological drug (R)-tolterodine and others were easily obtained after simple
Ruthenium‐Catalysed Asymmetric Intramolecular Isomerization/Esterification Reaction: Direct Synthesis of Chiral Dihydrocoumarins
作者:Lingzi Zhao、Xuchao Wang、Qing Qiang、Xingwei Zhao、Feipeng Liu、Shenci Lu、Zi‐Qiang Rong
DOI:10.1002/cjoc.202400084
日期:2024.8.15
An asymmetric isomerization/intramolecular coupling reaction of allylic alcohols to synthesize chiral dihydrocoumarins was successfully accomplished through ruthenium catalysis. This method demonstrates a wide substrate applicability, excellent tolerance for various functional groups, and good enantioselectivities (up to 90% ee). It provides a convenient pathway to produce a diverse range of structurally
6-Chloro-2,3-dihydro-4H-1-benzopyran-2-carboxylic acid, a rigid analogue of clofibric acid, the active metabolite of the antilipidemic drug clofibrate, has been prepared together with two isomers, 6-chloro-2,3-dihydro-4H-1-benzopyran-3- and 4-carboxylic acids. The three acids have been resolved into their optical antipodes and the absolute configuration established by chemical correlation.