Synthesis of heteroatom-containing pyrrolidine derivatives based on Ti(O- i Pr)4 and EtMgBr-catalyzed carbocyclization of allylpropargyl amines with Et2Zn

Rita N Kadikova; Ilfir R Ramazanov; Azat M Gabdullin; Oleg S Mozgovoj; Usein M Dzhemilev

doi:10.1039/d0ra02677h

Synthesis of heteroatom-containing pyrrolidine derivatives based on Ti(O- i Pr)₄ and EtMgBr-catalyzed carbocyclization of allylpropargyl amines with Et₂Zn

RSC Adv. 2020 May 7;10(30):17881-17891. doi: 10.1039/d0ra02677h. eCollection 2020 May 5.

Authors

Rita N Kadikova¹, Ilfir R Ramazanov¹, Azat M Gabdullin¹, Oleg S Mozgovoj¹, Usein M Dzhemilev¹

Affiliation

¹ Institute of Petrochemistry and Catalysis of Russian Academy of Sciences 141 Prospekt Oktyabrya Ufa 450075 Russian Federation kadikritan@gmail.com.

Abstract

The Ti(O-iPr)₄ and EtMgBr-catalyzed regio and stereoselective carbocyclization of N-allyl-substituted 2-alkynylamines with Et₂Zn, followed by deuterolysis or hydrolysis, affords the corresponding methylenepyrrolidine derivatives in high yields. It was found that Ti-Mg-catalyzed carbocyclization of N-allyl-substituted 2-alkynylamines with Et₂Zn is equally selective in dichloromethane, hexane, toluene, and diethyl ether. The reaction was tolerant to the presence of aryl, alkyl, trimethylsilyl, methoxymethyl and aminomethyl substituents on the alkyne. A selective method was proposed for the preparation of bis-pyrrolidine derivatives using Ti-Mg-catalyzed carbocyclization of bis-allylpropargyl amines with Et₂Zn.