One-Pot Oxidation and Bromination of 3,4-Diaryl-2,5-dihydrothiophenes Using Br<sub>2</sub>: Synthesis and Application of 3,4-Diaryl-2,5-dibromothiophenes
作者:Yizhe Dang、Yi Chen
DOI:10.1021/jo071172i
日期:2007.8.31
(1b−5b) was synthesized by a one-pot reaction of 3,4-diaryl-2,5-dihydrothiophenes with Br2 reagent in excellent yield (83−92%). It was found that Br2 performed a double function (oxidation and bromination) during the conversion of 3,4-diaryl-2,5-dihydrothiophenes to 3,4-diaryl-2,5-dibromothiophenes. The application of 3,4-diaryl-2,5-dibromothiophenes used as building blocks was also investigated. Employing
Asymmetric Synthesis of Chiral Dihydrothiopyrans via an Organocatalytic Enantioselective Formal Thio [3 + 3] Cycloaddition Reaction with Binucleophilic Bisketone Thioethers
An unprecedented organocatalytic highly enantioselective approach to a 3,4-dihydro-2H-thiopyran scaffold with two contiguous stereogenic centers has been implemented through a formal thio [3 + 3] cycloaddition process involving a Michael–aldol condensation cascade sequence. Notably, a new class of binucleophilic bisketone thioethers is designed for the process. Furthermore, the fine-tuning of their
The attempted seleniumdioxide oxidation of substituted diphenacyl sulfides in anticipation of further functionalization led to a series of α -ketoacids 3 via oxidation followed by C‒S bond cleavage. Two minor products, 5 and 6, have also been isolated and a mechanistic pathway for the formation of 3, 5 and 6 has been proposed. GRAPHICAL ABSTRACT
simple and efficient protocol for the construction of substituted piperazines, piperidines, thiomorpholines, decahydroquinolines, perhydrocyclopenta[b]pyridine, and pyrrolidines bearing N-hydroxy substituents through intramolecularreductivecyclization of diketoximes using sodium cyanoborohydride is described.