An unusual formal oxy transposition of vinylogous β-silyloxy-cyclobutanone 1（a 1,5-difunctionalized substrate） under mild acidic conditions（aqueous HF in CH3CN at 0℃） to the decalinic y-lactone 2 was described.A...An unusual formal oxy transposition of vinylogous β-silyloxy-cyclobutanone 1（a 1,5-difunctionalized substrate） under mild acidic conditions（aqueous HF in CH3CN at 0℃） to the decalinic y-lactone 2 was described.A plausible mechanistic pathway involving the Grob-type fragmentation and intramolecularγ-Iactonization was proposed.展开更多
A novel strategy was developed for a rapid access to the naturally occurring racemic neoclausenamide and its analogs, which featured a highly erythro-selective vinylogous Mukaiyama type reaction （dr= 12：1） and a hi...A novel strategy was developed for a rapid access to the naturally occurring racemic neoclausenamide and its analogs, which featured a highly erythro-selective vinylogous Mukaiyama type reaction （dr= 12：1） and a highly diastereoselective tandem conjugate addition-Davis oxidation ofN-Boc-pyrrol-2（5H）-one 5 （dr= 10：1）. Remarka- bly, the skeleton of neoclausenamide, namely 8n, an analog of neoclausenamide, was built in just two steps with all the four stereogenic centers （relative stereochemistry） established correctly and in excellent diastereoselectivities.展开更多
(E)-α,β-Unsaturated pyrazoleamides undergo facile dienolization to furnish copper(I)-(1Z,3Z)-dienolates as the major in the presence of a copper(I)-(R)-DTBM-SEGPHOS catalyst and EtgN,which react with aldimines to af...(E)-α,β-Unsaturated pyrazoleamides undergo facile dienolization to furnish copper(I)-(1Z,3Z)-dienolates as the major in the presence of a copper(I)-(R)-DTBM-SEGPHOS catalyst and EtgN,which react with aldimines to afford syn-vinylogous products as the major dia-stereoisomers in high regio-and enantioselectivities.In some cases,the diastereoselectivity is low,possibly due to the low ratio of copper(I)-(1Z,3Z)-dienolates to copper(I)-(1Z,3E)-dienolates.展开更多
基金financial support from National Natural Science Foundation of China(NSFC,Nos.21302177,21672049 and 21672030)
文摘An unusual formal oxy transposition of vinylogous β-silyloxy-cyclobutanone 1（a 1,5-difunctionalized substrate） under mild acidic conditions（aqueous HF in CH3CN at 0℃） to the decalinic y-lactone 2 was described.A plausible mechanistic pathway involving the Grob-type fragmentation and intramolecularγ-Iactonization was proposed.
文摘A novel strategy was developed for a rapid access to the naturally occurring racemic neoclausenamide and its analogs, which featured a highly erythro-selective vinylogous Mukaiyama type reaction （dr= 12：1） and a highly diastereoselective tandem conjugate addition-Davis oxidation ofN-Boc-pyrrol-2（5H）-one 5 （dr= 10：1）. Remarka- bly, the skeleton of neoclausenamide, namely 8n, an analog of neoclausenamide, was built in just two steps with all the four stereogenic centers （relative stereochemistry） established correctly and in excellent diastereoselectivities.
基金We gratefully acknowledge the financial support from the"Thousand Youth Talents Plan",the National Natural Science Foundation of China(Nos.21672235,21871287,21922114)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XD20000000)+1 种基金CAS Key Laboratory of Synthetic Chemistry of Natural SubstancesShanghai Institute of Organic Chemistry.
文摘(E)-α,β-Unsaturated pyrazoleamides undergo facile dienolization to furnish copper(I)-(1Z,3Z)-dienolates as the major in the presence of a copper(I)-(R)-DTBM-SEGPHOS catalyst and EtgN,which react with aldimines to afford syn-vinylogous products as the major dia-stereoisomers in high regio-and enantioselectivities.In some cases,the diastereoselectivity is low,possibly due to the low ratio of copper(I)-(1Z,3Z)-dienolates to copper(I)-(1Z,3E)-dienolates.
