Dataset Information


[Co(TPP)]-Catalyzed Formation of Substituted Piperidines.

ABSTRACT: Radical cyclization via cobalt(III)-carbene radical intermediates is a powerful method for the synthesis of (hetero)cyclic structures. Building on the recently reported synthesis of five-membered N-heterocyclic pyrrolidines catalyzed by CoII porphyrins, the [Co(TPP)]-catalyzed formation of useful six-membered N-heterocyclic piperidines directly from linear aldehydes is presented herein. The piperidines were obtained in overall high yields, with linear alkenes being formed as side products in small amounts. A DFT study was performed to gain a deeper mechanistic understanding of the cobalt(II)-porphyrin-catalyzed formation of pyrrolidines, piperidines, and linear alkenes. The calculations showed that the alkenes are unlikely to be formed through an expected 1,2-hydrogen-atom transfer to the carbene carbon. Instead, the calculations were consistent with a pathway involving benzyl-radical formation followed by radical-rebound ring closure to form the piperidines. Competitive 1,5-hydrogen-atom transfer from the ?-position to the benzyl radical explained the formation of linear alkenes as side products.

SUBMITTER: Lankelma M 

PROVIDER: S-EPMC6563703 | BioStudies | 2019-01-01

REPOSITORIES: biostudies

Similar Datasets

2017-01-01 | S-EPMC5561469 | BioStudies
2020-01-01 | S-EPMC7317878 | BioStudies
1000-01-01 | S-EPMC5052654 | BioStudies
2010-01-01 | S-EPMC2944903 | BioStudies
2015-01-01 | S-EPMC4822695 | BioStudies
1000-01-01 | S-EPMC6137206 | BioStudies
1000-01-01 | S-EPMC4073881 | BioStudies
2014-01-01 | S-EPMC4201326 | BioStudies
2007-01-01 | S-EPMC2590667 | BioStudies
2008-01-01 | S-EPMC2674573 | BioStudies