In the optimization of the ring-opening reaction of thiophene-1,1-dioxides, 3-bromo-2,5-dimethylthiophene-1,1-dioxide (1) and 2-(2-hydroxyethyl)piperidine (7) were chosen as model reagents. Solvent, temperature, molar ratio between amine and dioxide and the amount of solvent were variables included in the optimization. A central composite design was chosen for the investigation and a canonical analysis
Stereoselectivities of the intramolecular Diels-Alder reaction in the azanona- and azadecatriene series. Preparation of some polyhydroisoindoles, polyhydroisoquinolines, decahydropyrido[2,1-a]isoindoles and decahydro-2H-pyrido[1,2-b]isoquinolines
polyhydroisoquinolines were prepared through ring-opening of 3-bromo-2,5-dimethylthiophene-1,1-dioxide (1) with amines 2 and 3 giving trienes 5 and 6, which could be cyclized in an intramolecular Diels-Alderreaction (IMDA). Decahydropyrido[2,1-a]isoindoles and decahydro-2H-pyrido[1,2-b]isoquinolines were prepared stereoselectively (92–99%) in four steps in 60–63% overall yields via a TiCl4 catalyzed IMDA
取代的多氢异吲哚和多氢异喹啉是通过将3-溴-2,5-二甲基噻吩-1,1-二氧化物(1)与胺2和3开环而制得的三烯5和6,可以在分子内Diels-Alder中环化。反应(IMDA)。十氢吡啶并[2,1- a ]异吲哚和十氢2 H-吡啶[1,2- b ]异喹啉通过TiCl 4催化的IMDA分四步以60-63%的总收率立体制备(92-99%)。使用半经验和从头算对IMDA中的立体选择性进行讨论 计算也被提出。
A stereoselective synthesis of dialkylaminomethyl substituted halobutadienes via amine induced ring-opening of thiophene-1,1-dioxides
作者:S. Gronowitz、A. Hallberg、G. Nikitidis
DOI:10.1016/s0040-4020(01)87664-x
日期:1987.1
1-dioxide in good yields. The reaction of 3-chloro- and 3-bromo-2,5-dimethylthiophene-1, 1-dioxide with piperidine, pyrrolidine and morpholine at 100 °C intoluene on the other hand gave only one of the four possible isomeric dialkylaminomethyl-substituted hatobutadienes as main products and dialkylamino-substituted cis-2,3-dihydrothiophene-1,1-dioxides as by-products. Possible reaction paths are discussed.