Asymmetric Diels–Alder reactions of 2-fluoroacrylic acid derivatives. Part 1: The construction of fluorine substituted chiral tertiary carbon
作者:Hisanaka Ito、Akio Saito、Takeo Taguchi
DOI:10.1016/s0957-4166(98)00195-5
日期:1998.6
For the construction of chiral monofluorinated tertiary carbons, we have examined the asymmetric Diels–Alder reaction of 2-fluoroacrylic acid derivatives bearing a chiral oxazolidinone moiety. Under diethylaluminum chloride catalyzed conditions at −100°C, the reaction of 1 with isoprene proceeded smoothly with high diastereoselectivity.
of an amine was used to not only simplify the preparation of the catalysts but also increase Lewis acidity of the boron atom. The in situ generated borenium salts showed exceptional Lewis acidity and successfully catalyzed asymmetric Diels–Alderreactions of cyclopentadiene and dienophiles in excellent yields and enantioselectivities. The NMR studies of these oxathiaborolium structures were reported
Individual isomers of endo-bicyclo[2.2.1]heptyl adenosine
申请人:WARNER-LAMBERT COMPANY
公开号:EP0291051A2
公开(公告)日:1988-11-17
(1R-endo) or (1S-endo)-N-bicyclo[2.2.1]heptyl adenosine and pharmaceutically acceptable acid addition salts having highly desirable antihypertensive properties and unexpected A₁ and A₂ receptor binding activity, processes for their manufacture and pharmaceutical compositions and methods for using said compounds and compositions.
Transesterification of N-acyloxazolidinones with alcohol by lanthanum(III) Iodide
作者:Shin-ichi Fukuzawa、Yuki Hongo
DOI:10.1016/s0040-4039(98)00521-8
日期:1998.5
Transesterification of N-acyloxazolidinones by treatment with an alcohol and lanthanum(III) iodide gives the corresponding esters in good to excellent yields under mild conditions with negligible racemization. (C) 1998 Elsevier Science Ltd. All rights reserved.
EVANS, D. A.;CHAPMAN, K. T.;BISAHA, J., J. AMER. CHEM. SOC., 110,(1988) N 4, 1238-1256