An original approach to 5,6-dihydroindolizines from 1-allylpyrroles by a tandem hydroformylation/cyclization/dehydration sequence
摘要:
6-Methyl-5,6-dihydroindolizine and 3- or 2-ethyl derivatives were obtained via a one-pot hydroformylation/cyclization/dehydration sequence starting from 1-(2-methyl-2-propenyl)pyrroles. 7-Phenyl-5,6-dihydroindolizine and 5-methyl-5,6-dihydroindolizine were similarly synthesized. An easily occurring electrophilic aromatic substitution by the carbon atom of the carbonyl group on the cl-position of the pyrrole ring with the formation of the six-membered ring is the key-step of the process. (C) 2001 Elsevier Science Ltd. All rights reserved.
An original approach to 5,6-dihydroindolizines from 1-allylpyrroles by a tandem hydroformylation/cyclization/dehydration sequence
摘要:
6-Methyl-5,6-dihydroindolizine and 3- or 2-ethyl derivatives were obtained via a one-pot hydroformylation/cyclization/dehydration sequence starting from 1-(2-methyl-2-propenyl)pyrroles. 7-Phenyl-5,6-dihydroindolizine and 5-methyl-5,6-dihydroindolizine were similarly synthesized. An easily occurring electrophilic aromatic substitution by the carbon atom of the carbonyl group on the cl-position of the pyrrole ring with the formation of the six-membered ring is the key-step of the process. (C) 2001 Elsevier Science Ltd. All rights reserved.
Synthesis of 5,6,7,8-tetrahydroindolizines<i>via</i>a domino-type transformation based on the rhodium catalyzed hydroformylation of<i>N</i>-(β-methallyl)pyrroles
Variously substituted 5,6,7,8-tetrahydroindolizines can be easily synthesized via a domino reactions sequence under rhodium catalyzed hydroformylation of N-(β-methallyl)pyrroles. The later are readily prepared from properly functionalized pyrroles via phase-transfer N-allylation in the presence of 18-crown-6 and potassium tert-butoxide.
6-Methyl-5,6-dihydroindolizine and 3- or 2-ethyl derivatives were obtained via a one-pot hydroformylation/cyclization/dehydration sequence starting from 1-(2-methyl-2-propenyl)pyrroles. 7-Phenyl-5,6-dihydroindolizine and 5-methyl-5,6-dihydroindolizine were similarly synthesized. An easily occurring electrophilic aromatic substitution by the carbon atom of the carbonyl group on the cl-position of the pyrrole ring with the formation of the six-membered ring is the key-step of the process. (C) 2001 Elsevier Science Ltd. All rights reserved.