Polysubstituted Piperidines via Iodolactonization: Application to the Asymmetric Synthesis of (+)-Pseudodistomin D
摘要:
Conjugate addition of lithium (S)-N-allyl-N-(alpha-methyl-p-methoxybenzyl)amide to methyl (E,E)-hepta-2,5-dienoate furnished the corresponding beta-amino ester. N-Protecting group manipulation, ring-closing metathesis, and ester hydrolysis gave enantiopure [N(1')-tert-butoxycarbonyl-1,2,3,6-tetrahydropyridin-2'-yl]ethanoic acid. Subsequent iodolactonization gave a bicyclic iodolactone scaffold. This key intermediate was elaborated to (+)-pseudodistomin D [in >99% ee and 7% yield over 16 steps from methyl (E,E)-hepta-2,5-dienoate].
Polysubstituted Piperidines via Iodolactonization: Application to the Asymmetric Synthesis of (+)-Pseudodistomin D
摘要:
Conjugate addition of lithium (S)-N-allyl-N-(alpha-methyl-p-methoxybenzyl)amide to methyl (E,E)-hepta-2,5-dienoate furnished the corresponding beta-amino ester. N-Protecting group manipulation, ring-closing metathesis, and ester hydrolysis gave enantiopure [N(1')-tert-butoxycarbonyl-1,2,3,6-tetrahydropyridin-2'-yl]ethanoic acid. Subsequent iodolactonization gave a bicyclic iodolactone scaffold. This key intermediate was elaborated to (+)-pseudodistomin D [in >99% ee and 7% yield over 16 steps from methyl (E,E)-hepta-2,5-dienoate].
(−)-Pseudodistomin E: First Asymmetric Synthesis and Absolute Configuration Assignment
作者:Stephen G. Davies、Ai M. Fletcher、Paul M. Roberts、James E. Thomson、David Zimmer
DOI:10.1021/acs.orglett.7b00434
日期:2017.4.7
(−)-Pseudodistomin E has been prepared for the first time, allowing its structure and absoluteconfiguration to be confirmed. The established conjugate addition of lithium (S)-N-allyl-N-(α-methyl-p-methoxybenzyl)amide to methyl (E,E)-hepta-2,5-dienoate generated the C(2)-stereocenter, and iodolactonisation of a derivative generated the remaining two stereogenic centers. Ensuing iodide displacement