of main observation and conclusion Allenes are a class of very important compounds and the development of straightforward,efficient,and highly enantioselective synthetic strategies for allenes have attracted extensive...of main observation and conclusion Allenes are a class of very important compounds and the development of straightforward,efficient,and highly enantioselective synthetic strategies for allenes have attracted extensive interests.Along this line,it is well known that aryl-substituted allenes may be readily racemized,thus,difficult to prepare in high ee.Herein,an efficient palladium-catalyzed nucleophilic allenylation of malonates w ith racemic 4-aryl-2,3-butadienyl carbonates has been developed.The selectivity issue of mono-vs.bis-allenylation with 2-non-substituted malonates has been addressed.By utilizing(R)-(-)-DTBM-SEGPHOS(5,5'-bisldi(3,5,-di-t-butyl-A-methoxyphenyOphosphino)-4,4'-bi-l,3-benzodioxole)as a chiral ligand,various aryl-substituted allenes and bisallenes have been prepared with good to excellent yields with high chemoselectivity and enantioselectivity under mild reaction conditions.Au-catalyzed cycloisomerization and APK(allenic Pauson-Khand)reactions affording optically active mono-and bicyclic products have been demonstrated.展开更多
Chiral amines are widely found in nature,and many of them possess significant biological and synthetic value.The catalytic asymmetric syntheses of optically active amines have gained enormous interest.Currently,fruitf...Chiral amines are widely found in nature,and many of them possess significant biological and synthetic value.The catalytic asymmetric syntheses of optically active amines have gained enormous interest.Currently,fruitful and prime strategies for obtaining them rely on homogeneous catalysts.Due to the pressure to develop highly economical and environmentally friendly homogeneous catalysis.展开更多
基金Financial support from the National Natural Science Foundation of China(Nos.21690063 and 21572202)is greatly appreciated.We thank Mr.Jie Lin in this group for reproducing the preparation of(Ra)-3cb and(Ra,Ra)-4ea.Shengming Ma is a Qiu ShiAdjunct Professor at Zhejiang University.
文摘of main observation and conclusion Allenes are a class of very important compounds and the development of straightforward,efficient,and highly enantioselective synthetic strategies for allenes have attracted extensive interests.Along this line,it is well known that aryl-substituted allenes may be readily racemized,thus,difficult to prepare in high ee.Herein,an efficient palladium-catalyzed nucleophilic allenylation of malonates w ith racemic 4-aryl-2,3-butadienyl carbonates has been developed.The selectivity issue of mono-vs.bis-allenylation with 2-non-substituted malonates has been addressed.By utilizing(R)-(-)-DTBM-SEGPHOS(5,5'-bisldi(3,5,-di-t-butyl-A-methoxyphenyOphosphino)-4,4'-bi-l,3-benzodioxole)as a chiral ligand,various aryl-substituted allenes and bisallenes have been prepared with good to excellent yields with high chemoselectivity and enantioselectivity under mild reaction conditions.Au-catalyzed cycloisomerization and APK(allenic Pauson-Khand)reactions affording optically active mono-and bicyclic products have been demonstrated.
基金Financial support for this work was received from the Science and Technology Research Program of Chongqing Municipal Education Commission(no.KJQN201900817)Research Foundation for Talented Scholars(no.1956047)Key Disciplines of Chemical Engineering and Technology in Chongqing Colleges and Universities during the 13th Five Year Plan.
文摘Chiral amines are widely found in nature,and many of them possess significant biological and synthetic value.The catalytic asymmetric syntheses of optically active amines have gained enormous interest.Currently,fruitful and prime strategies for obtaining them rely on homogeneous catalysts.Due to the pressure to develop highly economical and environmentally friendly homogeneous catalysis.
