Catalytic Enantioselective Silylation of Acyclic and Cyclic Triols: Application to Total Syntheses of Cleroindicins D, F, and C
作者:Zhen You、Amir H. Hoveyda、Marc L. Snapper
DOI:10.1002/anie.200805338
日期:2009.1.5
Pick one out of three: Acyclic and cyclic 1,2,3‐triols are silylated with exceptional site‐ and enantioselectivity by a small‐molecule catalyst to afford silyl ethers having a neighboring diol moiety. The new process is applied to the enantioselectivetotalsyntheses of three cleroindicins, natural products isolated from a plant used in China to battle malaria and rheumatism.
The elusive nature of noncovalent π-interactions leads to their infrequent use as a design element in challenging chemical reactions. Stereocontrolling models based on coordinated noncovalent π-interactions were used for the asymmetric dihydroxylation of 1,1-disubstituted aliphatic alkenes. By introduction of a substituted phthalazine ring into the alkene substrates, the enantioselectivity reached
Preparation of enantiomerically pure (R)-2-butyryloxymethylglycidol by lipase-catalyzed asymmetric hydrolysis
作者:Young-Bae Seu、Taeg-Kyeong Lim、Chang-Jin Kim、Sun-Chul Kang
DOI:10.1016/0957-4166(95)00397-5
日期:1995.12
Optically active epoxy alcohol, (R)-2-butyryloxymethylglycidol 3 which is the precursor of a tert-alcohol chiral building block was obtained in high enantiomeric purity, 98.7% e.e., by lipase-catalyzed asymmetric hydrolysis using a phosphate buffer and organic co-solvent system in 95% of chemical yield.
Asymmetric synthesis of ()-(+)- and ()-(-)-2,2,4-trimethyl-4-(hydroxymethyl)-1,3-dioxolane of high enantiomeric purity
作者:David Tanner、Peter Somfai
DOI:10.1016/s0040-4020(01)96082-x
日期:1986.1
The title compounds, and ', are readily available in four steps from 2-benzyloxymethyl-2-propen-1-ol, the key step being Sharpless asymmetric epoxidation to give the chiral epoxides or '. The total chemical yield of or ' is 50%, the final products being obtained essentially optically pure. By suitable protecting group manipulation, both title enantiomers can be produced from either of the antipodal