The stereochemistry of trans-cyclooctene derivatives
作者:R.D. Bach、U. Mazur、I. Hamama、S.K. Lauderback
DOI:10.1016/0040-4020(72)88003-7
日期:1972.1
X-Ray and NMR data are presented which suggest that trans-cyclooctene, 9,9-dibromo-trans-bicyclo[6.1.0]nonane, trans-bicyclo[6.1.0]nonane and trans-cyclooctene oxide exist in a distorted crown conformation. The synthesis of optically active trans-bicyclo[6.1.0]nonane and trans-cyclooctene oxide is described.
An efficient one-pot two-step procedure for asymmetric synthesis of piperidine-fused trans-cycloalkenes is reported. The method comprises the initial enantioselective installation of another cyclopropane ringonto methylenecyclopropanes and the subsequent thermal skeletal rearrangement in which the installed and inherent cyclopropane rings are both opened. A concerted mechanism is proposed for the
Dialkylation of gem-dibromocyclopropanes with trialkylmanganate and manganese(II) chloride-catalyzed reaction with alkylmagnesium bromide
作者:Rie Inoue、Hiroshi Shinokubo、Koichiro Oshima
DOI:10.1016/0040-4039(96)01082-9
日期:1996.7
gem-dibromocyclopropanes with trialkylmanganate, derived from manganese(II) chloride and three equivalents of Grignard reagent or alkyllithium, followed by an addition of electrophiles provided dialkylated cyclopropanes in good yields. It was found the reaction with alkylmagnesium halide proceeded in the presence of a catalytic amount of manganese(II) chloride.
作者:Dietmar Seyferth、Robert L. Lambert、Michel Massol
DOI:10.1016/s0022-328x(00)89503-0
日期:1975.4
A number of α-bromocyclopropyllithium reagents have been prepared at low temperature (−90° to −100°) in THF or THF/Et2O medium by reaction of n-butyllithium with the respective gem-dibromocyclopropane. Reactions of these new lithium reagents with concentrated HCl, trimethylchlorosilane, dimethyldichlorosilane, trimethyltin chloride, dimethyltin dichloride, dimethyldichlorogermane, trimethyllead bromide
通过正丁基锂与相应的宝石-二溴环丙烷的反应,已在THF或THF / Et 2 O介质中于低温(-90°至-100°)下制备了多种α-溴环丙基锂试剂。描述了这些新的锂试剂与浓盐酸,三甲基氯硅烷,二甲基二氯硅烷,三甲基氯化锡,二甲基锡二氯化物,二甲基二氯锗烷,三甲基溴化铅,氯化汞和一些其他有机金属卤化物的反应。的一种新的异构化顺式-7-溴-反-7- lithionorcarane到反-7-溴-顺-7- lithionorcarane,通过稍微过量的7,7- dibromonorcarane的存在引起的,进行说明。
Sequential and highly stereoselective intermolecular radical additions of 2,3-cis-disubstituted 1,1-dibromo- and 1-bromocyclopropanes to electron-deficient olefins
作者:Yoo Tanabe、Ken-ichi Wakimura、Yoshinori Nishii
DOI:10.1016/0040-4039(96)00156-6
日期:1996.3
Novel and sequential intermolecular radicaladditions of 2,3-cis-disubstituted 1,1-dibromo- and 1-bromocyclopropanes to electron-deficient olefins proceeded with high stereoselectivity, i.e., in an exo-face addition manner. This highly stereoselectiveaddition was also applied to an intramolecular cyclization.