Several polystyrene-supported selenides and selenoxide have been prepared firstly. These novel reagents were treated with LDA to produce selenium stabilized carbanions, which reacted with aldehydes and alkyl halides, ...Several polystyrene-supported selenides and selenoxide have been prepared firstly. These novel reagents were treated with LDA to produce selenium stabilized carbanions, which reacted with aldehydes and alkyl halides, followed by selenoxide syn-elimination and [2,3] sigmatropic rearrangement respectively to give Z-allylic alcohols stereoselectively.展开更多
1 Introduction Heteroatom-stabilized carbenium ions have been widely recognized as potential electrophilic reagents.However,in contrast with the extensive works on thionium ion series,the highly labile character of se...1 Introduction Heteroatom-stabilized carbenium ions have been widely recognized as potential electrophilic reagents.However,in contrast with the extensive works on thionium ion series,the highly labile character of selenoxide functionalities has caused serious limitation in the synthetic use in spite of their wide potentiality as synthetic equivalents of electrophilic selonium ions.In this paper,novel generation of selonium ions and the synthetic uses of the species for Pummerer-typeα-functionalization and for cycloaddition by using the novel dienophilic behavior ofπ-conjugated selonium cations.展开更多
The organoselenium-induced ring-closure reaction of O-allyl oximes gave cyclic iminium salts, which reacted with Grignard reagents to produce N-alkyl-4-phenylselenoisoxazolidines. 2,5-Dihydroisoxazoles could be obtain...The organoselenium-induced ring-closure reaction of O-allyl oximes gave cyclic iminium salts, which reacted with Grignard reagents to produce N-alkyl-4-phenylselenoisoxazolidines. 2,5-Dihydroisoxazoles could be obtained in good yields by subsequent selenoxide syn-elimination.展开更多
文摘Several polystyrene-supported selenides and selenoxide have been prepared firstly. These novel reagents were treated with LDA to produce selenium stabilized carbanions, which reacted with aldehydes and alkyl halides, followed by selenoxide syn-elimination and [2,3] sigmatropic rearrangement respectively to give Z-allylic alcohols stereoselectively.
文摘1 Introduction Heteroatom-stabilized carbenium ions have been widely recognized as potential electrophilic reagents.However,in contrast with the extensive works on thionium ion series,the highly labile character of selenoxide functionalities has caused serious limitation in the synthetic use in spite of their wide potentiality as synthetic equivalents of electrophilic selonium ions.In this paper,novel generation of selonium ions and the synthetic uses of the species for Pummerer-typeα-functionalization and for cycloaddition by using the novel dienophilic behavior ofπ-conjugated selonium cations.
基金Project supported by the National Natural Science Foundation of China (Nos. 20332060,20272050).
文摘The organoselenium-induced ring-closure reaction of O-allyl oximes gave cyclic iminium salts, which reacted with Grignard reagents to produce N-alkyl-4-phenylselenoisoxazolidines. 2,5-Dihydroisoxazoles could be obtained in good yields by subsequent selenoxide syn-elimination.
