Azatricycles from substituted pyridines. Synthesis and rearrangement of N-ethoxycarbonyl-2-azatricyclo[4.3.1.03,7]dec-8-enes.
作者:Grant R. Krow、Yoon B. Lee、Ramesh Raghavachari、Steven W. Szczepanski、Peter V. Alston
DOI:10.1016/s0040-4020(01)82393-0
日期:1991.9
The scope and relative rates of intramolecular cycloaddition reactions of methyl-substituted 2-[3-butenyl]-1,2-dihydropyridines have been studied. Cycloadducts can be rearranged to upon reaction with bromine, except when olefinic methyl groups are present.
rac-trans-haloalkyl epoxides 1a−8a using the epoxide hydrolase activity of whole bacterial cells furnished the corresponding vicinal diols 1b−8b as intermediates; these (spontaneously) underwent ring closure to yield cyclic products 1c−6c through an enzyme-triggered cascade reaction. In particular, cis-configured substrates (1a, 3a, 5a, 7a) were transformed in an enantioconvergent fashion, which resulted
使用整个细菌细胞的环氧水解酶活性对 2,3-二取代外消旋-顺-和外消旋-反-卤代烷基环氧化物 1a-8a 进行生物催化水解,得到相应的邻位二醇 1b-8b 作为中间体;这些(自发地)经历闭环以通过酶触发的级联反应产生环状产物 1c-6c。特别是,顺式构型的底物(1a、3a、5a、7a)以对映收敛方式转化,导致从外消旋体中形成 100% des 和高达 92% ees 的单一立体异构产物。
Manganese (III) based oxidative free-radical cyclizations. 3. Polycyclization reactions proceeding through secondary radicals.
作者:Raju Mohan、Steven A. Kates、Mark A. Dombroski、Barry B. Snider
DOI:10.1016/s0040-4039(01)81004-2
日期:1987.1
Oxidativecyclizations of 3, 14, 18 and 21 with Mn(OAc)3 ·2H2O give the tricyclic products 6, 15, 19 and 23, respectively, in good yield. These reactions proceed through a monocyclic secondary radical which adds to the benzene ring prior to the second oxidation.
Peroxycarbenium-Mediated C−C Bond Formation: Applications to the Synthesis of Hydroperoxides and Peroxides
作者:Patrick H. Dussault、In Quen Lee、Hyung-Jae Lee、Richard J. Lee、Q. Jason Niu、Jeffrey A. Schultz、Umesh R. Zope
DOI:10.1021/jo991714z
日期:2000.12.1
while SnCl(4) and trimethylsilyl triflate promote formation of peroxides. Lewis acid-promoted reactions of silylated hydroperoxyacetals furnish silylated hydroperoxides, which can be deprotected to homologated hydroperoxides. Hydroperoxyketals undergo Lewis acid-mediated allylation to furnish 1,2-dioxolanes via attack of hydroperoxide on the intermediate carbocation. Lewis acid-mediated cyclization
Pyridinium chloride and bromide react with 1,6-hexanediol through a complex multireactional chain process mostly furnishing unsaturated hydrocarbons, cyclic ethers, unsaturated halides and unsaturated alcohols. The similar transformations undergone by 5-hexene-1-ol and 1-hexanol under the same conditions suggest several hypotheses about the mechanism. Several original assignments from 13C NMR data
氯化吡啶鎓和溴化物通过复杂的多反应链过程与1,6-己二醇反应,主要提供不饱和烃,环醚,不饱和卤化物和不饱和醇。5-己烯-1-醇和1-己醇在相同条件下经历的相似转化表明了有关该机理的几种假设。来自13 C NMR数据的一些原始分配涉及确定产物的结构。