Osmium-Catalyzed Vicinal Oxyamination of Alkenes by <i>N</i>-(4-Toluenesulfonyloxy)carbamates
作者:Masruri、Anthony C. Willis、Malcolm D. McLeod
DOI:10.1021/jo301372y
日期:2012.10.5
N-(4-Toluenesulfonyloxy)carbamates based on a range of common amine protecting groups serve as preformed nitrogen sources in the intermolecular osmium-catalyzedoxyamination reaction of a variety of mono-, di-, and trisubstituted alkenes. The reactions occur with low catalyst loadings and good yields and afford high regioselectivity for unsymmetrically substituted alkenes.
Chiral resolution method for producing compounds useful in the synthesis of taxanes
申请人:——
公开号:US20030045743A1
公开(公告)日:2003-03-06
A method is provided for processing a solution having optical isomers to obtain a (2R,3S) target isomer:
1
wherein P
1
is H or a hydroxyl protecting group, R
1
is H, an alkyl group, an olefinic group or an aromatic group, and R
2
is H or R
3
CO, where R
3
is an alkyl group, an olefinic group, an aromatic group, an O-alkyl group, an O-olefinic group or an O-aromatic group, provided that R
1
is not H when R
3
is Ph and P
1
is H. The method includes passing the solution through a chromatographic stationary phase, such as S,S Whelk-O, that has a greater affinity for one of the target isomer and an optical isomer thereof. A portion of the solution with the target isomer is then collected. The solution may be a racemic mixture of (±)-N-CBZ-3-phenylisoserine ethyl ester.
Cinchona alkaloid ester derivatives as ligands in the asymmetric dihydroxylation and aminohydroxylation of alkenes
作者:Hui Chen、Qiao Feng Wang、Xiao Li Sun、Jing Luo、Ru Jiang
DOI:10.1016/j.mencom.2010.03.013
日期:2010.3
Cinchona alkaloid ester derivatives were adopted to asymmetric dihydroxylation and asymmetric aminohydroxylation reactions in excellent yields and enantiomeric excesses.
CHIRAL RESOLUTION METHOD FOR PRODUCING COMPOUNDS USEFUL IN THE SYNTHESIS OF TAXANES