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
Asymmetric vinylogous C–X bond formation is rarely achieved due to competitiveα-functionalization and the oxidative nature of electrophilic X+reagents.This process usually results in the decomposition of the low-val...Asymmetric vinylogous C–X bond formation is rarely achieved due to competitiveα-functionalization and the oxidative nature of electrophilic X+reagents.This process usually results in the decomposition of the low-valent chiral transition metal catalyst which obstructs catalytic efficiency.Herein,by means of copper(I)catalysis,an asymmetric vinylogous selenenylation of(E)-β,γ-unsaturated pyrazole amides is accomplished in high enantioselectivity.The substrate scope is demonstrated to be broad for both(E)-β,γ-unsaturated pyrazole amides and selenosulfonates.Dynamic deuteration and background reaction illustrate that the chiral copper(I)-SL-J008-1 complex plays a key role in both the efficient enolization of(E)-β,γ-unsaturated pyrazole amides and the achievement ofγ-selectivity.Subsequent control experiments reveal allylcopper(I)species as the operating nucleophiles in the enantioselective vinylogous selenenylation.Finally,the synthetic utility of the present methodology has been demonstrated by versatile transformations of the product.展开更多
Discovery of unprecedented donor-acceptor patterns can essentially enrich the chemistry of donor-acceptor cyclopropanes.We herein introduce a concept of vinylogous fluorine stabilizing effect,which guides rational des...Discovery of unprecedented donor-acceptor patterns can essentially enrich the chemistry of donor-acceptor cyclopropanes.We herein introduce a concept of vinylogous fluorine stabilizing effect,which guides rational design of a novel donor-acceptor cyclopropane employing gem-difluorovinyl group as the electron donor,namely dFVCP.Application of such dFVCPs in a[3+2]cycloaddition with aldehydes and a controlled ring-opening polymerization by a Mg(OTf)_(2)/DIPEA/C(sp^(3))-H initiator system have been demonstrated,providing direct access to fluorine-containing tetrahydrofurans and all-carbon main-chain polymers.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.
基金the National Key R&D Program of China(grant no.2024YFA1210700)the National Natural Science Foundation of China(grant no.22271302)+1 种基金the Science and Technology Commission of Shanghai Municipality(grant no.LJ2023103)the Strategic Priority Research Program of the Chinese Academy of Sciences(grant no.XDB0590000).
文摘Asymmetric vinylogous C–X bond formation is rarely achieved due to competitiveα-functionalization and the oxidative nature of electrophilic X+reagents.This process usually results in the decomposition of the low-valent chiral transition metal catalyst which obstructs catalytic efficiency.Herein,by means of copper(I)catalysis,an asymmetric vinylogous selenenylation of(E)-β,γ-unsaturated pyrazole amides is accomplished in high enantioselectivity.The substrate scope is demonstrated to be broad for both(E)-β,γ-unsaturated pyrazole amides and selenosulfonates.Dynamic deuteration and background reaction illustrate that the chiral copper(I)-SL-J008-1 complex plays a key role in both the efficient enolization of(E)-β,γ-unsaturated pyrazole amides and the achievement ofγ-selectivity.Subsequent control experiments reveal allylcopper(I)species as the operating nucleophiles in the enantioselective vinylogous selenenylation.Finally,the synthetic utility of the present methodology has been demonstrated by versatile transformations of the product.
基金supported by the National Natural Science Foundation of China(No.22101273)the Fundamental Research Fund for the Central Universities(WK9990000111)。
文摘Discovery of unprecedented donor-acceptor patterns can essentially enrich the chemistry of donor-acceptor cyclopropanes.We herein introduce a concept of vinylogous fluorine stabilizing effect,which guides rational design of a novel donor-acceptor cyclopropane employing gem-difluorovinyl group as the electron donor,namely dFVCP.Application of such dFVCPs in a[3+2]cycloaddition with aldehydes and a controlled ring-opening polymerization by a Mg(OTf)_(2)/DIPEA/C(sp^(3))-H initiator system have been demonstrated,providing direct access to fluorine-containing tetrahydrofurans and all-carbon main-chain polymers.
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.
