Enantioselective C−C Bond Cleavage Creating Chiral Quaternary Carbon Centers
摘要:
A chiral all-carbon benzylic quaternary carbon center is created by the asymmetric intramolecular addition/ring-opening reaction of a borylsubstituted cyclobutanone, which involves enantioselective ss-carbon elimination from a symmetrical rhodium cyclobutanolate. The asymmetric reaction was successfully applied to a synthesis of sesquiterpene, (-)-alpha-herbertenol.
Enantioselective Construction of Indanones from Cyclobutanols Using a Rhodium-Catalyzed C-C/C-H/C-C Bond Activation Process
作者:Nicolai Cramer、Tobias Seiser、Gino Cathomen
DOI:10.1055/s-0029-1219959
日期:2010.7
Enantioselective rhodium(I)-catalyzed reactions of tert-cyclobutanols lead via consecutive C-C/C-H/C-C bond activations to indanones with quaternary stereogenic centers.
Asymmetric Synthesis of All-Carbon Benzylic Quaternary Stereocenters via Cu-Catalyzed Conjugate Addition of Dialkylzinc Reagents to 5-(1-Arylalkylidene) Meldrum's Acids
作者:Eric Fillion、Ashraf Wilsily
DOI:10.1021/ja056692e
日期:2006.3.1
The asymmetric synthesis of all-carbon benzylic quaternary stereocenters has been successfully achieved through copper-catalyzed addition of dialkylzinc reagents to 5-(1-arylalkylidene) and 5-(dihydroindenylidene) Meldrum's acids in the presence of phosphoramidite ligand. The resulting benzyl-substituted Meldrum's acids and 1,1-disubstituted indanes were obtained in good yields and up to 99% ee. The significance of substituting the position para, meta, and ortho to the electrophilic benzylic center was highlighted. A benzyl Meldrum's acid product was further transformed to a 3,3-disubstituted 1-indanone and a beta,beta-disubstituted pentanoic acid.
The absolute configuration of physostigmine
作者:R.K. Hill、G.R. Newkome
DOI:10.1016/s0040-4020(01)82698-3
日期:1969.1
Enantioselective C−C Bond Cleavage Creating Chiral Quaternary Carbon Centers
A chiral all-carbon benzylic quaternary carbon center is created by the asymmetric intramolecular addition/ring-opening reaction of a borylsubstituted cyclobutanone, which involves enantioselective ss-carbon elimination from a symmetrical rhodium cyclobutanolate. The asymmetric reaction was successfully applied to a synthesis of sesquiterpene, (-)-alpha-herbertenol.