Stereoselective Synthesis of 5-(1-Hydroxyalkyl)-2-pyrrolidinones Utilizing Oxidation of 5-Alkylidene-2-pyrrolidinones to Acyliminium Ion Precursors
摘要:
A general method was devised for the LiN(TMS)(2)/AgOTf (=2:1)-catalyzed intramolecular (5-exo-dig) cyclization of beta -alkynylamides 1 possessing alkyl, aryl or no functional groups at the terminal alkynes, to 5-alkylidene-2-pyrrolidinones 2. These 5-alkylidene-2-pyrrolidinones were oxidized to the diol-type alkoxylactams 3 by dimethyldioxirane (DMD) or mCPBA in MeOH. These alkoxylactams are useful as tertiary N-acyliminium ion precursors for the synthesis of threo-5-(1-hydroxyalkyl)-2-pyrrolidinone derivatives 5. (C) 2000 Elsevier Science Ltd. All rights reserved.
Stereoselective Synthesis of 5-(1-Hydroxyalkyl)-2-pyrrolidinones Utilizing Oxidation of 5-Alkylidene-2-pyrrolidinones to Acyliminium Ion Precursors
摘要:
A general method was devised for the LiN(TMS)(2)/AgOTf (=2:1)-catalyzed intramolecular (5-exo-dig) cyclization of beta -alkynylamides 1 possessing alkyl, aryl or no functional groups at the terminal alkynes, to 5-alkylidene-2-pyrrolidinones 2. These 5-alkylidene-2-pyrrolidinones were oxidized to the diol-type alkoxylactams 3 by dimethyldioxirane (DMD) or mCPBA in MeOH. These alkoxylactams are useful as tertiary N-acyliminium ion precursors for the synthesis of threo-5-(1-hydroxyalkyl)-2-pyrrolidinone derivatives 5. (C) 2000 Elsevier Science Ltd. All rights reserved.
Regio‐ and Stereoselective 1,2‐Oxyhalogenation of Non‐Conjugated Alkynes via Directed Nucleopalladation: Catalytic Access to Tetrasubstituted Alkenes**
Palladium(II)-catalyzedregio- and stereoselective oxyhalogenation of unactivated internal alkynes is facilitated by a structurally tuned bidentate directing auxiliary, providing rapid access to tetrasubstituted alkenes that can be further diversified into valuable products.
钯 (II) 催化的未活化内部炔烃的区域选择性和立体选择性卤化作用通过结构调整的双齿定向助剂促进,提供快速获得四取代烯烃的途径,这些烯烃可以进一步多样化为有价值的产品。