Chiral Silver Phosphate-Catalyzed Cycloisomeric Kinetic Resolution of α-Allenic Alcohols
摘要:
A kinetic resolution of a-allenic alcohols is realized through chiral silver phosphate-catalyzed cycloisomerization with high stereoselectivity (selectivity factor up to 189) and tolerance of a variety of functional groups. A mechanistic model is proposed to interpret the origin of the high stereoselectivity and broad substrate scope.
Allenylic Carbonates in Enantioselective Iridium-Catalyzed Alkylations
作者:David A. Petrone、Mayuko Isomura、Ivan Franzoni、Simon L. Rössler、Erick M. Carreira
DOI:10.1021/jacs.8b01416
日期:2018.4.4
products obtained was highlighted in a variety of stereoselective transition metal-catalyzed difunctionalization reactions. Furthermore, a combination of experimental and theoretical studies provide support for a putative reactionmechanism wherein enantiodetermining C-C coupling occurs via nucleophilic attack on a highly planarized aryl butadienylium π-system that is coordinated to the Ir center in an η2-fashion
Catalytic Enantioselective Allenylation Reactions of Aldehydes with Tethered Bis(8-quinolinolato) (TBOx) Chromium Complex
作者:Guoyao Xia、Hisashi Yamamoto
DOI:10.1021/ja0679578
日期:2007.1.1
The utility of the new class of chiral ligand, tethered bis(8-quinolinol) (TBOxH), is further explored. Its chromiumcomplex, TBOxCr(III)Cl, effectively catalyzes the asymmetric allenylation reactions of various aldehydes at room temperature with high yields (up to 91%) and high enantioselectivities (up to 97% ee). The scope of the present method is shown to be wide, and this method represents an efficient
Rhodium-catalyzed direct coupling of biaryl pyridine derivatives with internal alkynes
作者:Jun Zheng、Shu-Li You
DOI:10.1039/c4cc02822h
日期:——
Axially chiral biaryls were synthesized by an isoquinoline or 2-pyridine-directed Rh(iii)-catalyzed dual C–H cleavage and coupling with internal alkynes.
Practical and efficient catalytic asymmetric allylic transfer reactions of achiral aldehydes with tin reagents promoted by BINOL-Ti(IV) complex are achieved with high enantioselectivity by the utilization of subjoined Lewis acid, B(OMe)3.
Efficient Synthesis of Optically Active 2,3-Allenols via the Simple CuBr-Mediated Reaction of Optically Active Propargylic Alcohols with Paraformaldehyde
作者:Shengming Ma、Hairong Hou、Shimin Zhao、Guangwei Wang
DOI:10.1055/s-2002-33656
日期:——
Enantiomerically enriched 2,3--allenols were prepared by the GuBr-mediated homologation of the relatively easily available opticallyactive teminal propargylic alcohols with paraformaldehyde in the presence of diisopropylamine.