An easy and efficient method for the synthesis of multisubstituted cyclopropane derivatives from electron-deficicent alkenes with 2-bromo-1,3-propanedione compounds was described.For this method,ethylα-cyanocinnamate...An easy and efficient method for the synthesis of multisubstituted cyclopropane derivatives from electron-deficicent alkenes with 2-bromo-1,3-propanedione compounds was described.For this method,ethylα-cyanocinnamate derivatives 1 andβ,β-dicyanostyrene derivatives 4 can all smoothly reacted with 2-bromo-1,3-propanedione compounds 2 to afford the corresponding multisubstituted cyclopropane derivatives 3 and 5 in good to excellent yields(up to 100%)promoted by anhydrous K3PO4 in DMF at room temperature,respectively.A possible mechanism of this reaction was proposed.Structures of all the products were confirmed by ^1H NMR,^13C NMR and HRMS.展开更多
Tandem asymmetric double Michael addition/internal nucleophilic substitution of the novel chiral source, 5-(l-menthyloxy)-3-bromo-2(5H)-furanone with nucleophilic alcohol compounds has been investigated. The tandem as...Tandem asymmetric double Michael addition/internal nucleophilic substitution of the novel chiral source, 5-(l-menthyloxy)-3-bromo-2(5H)-furanone with nucleophilic alcohol compounds has been investigated. The tandem asymmetric reaction can afford four new stereogenic centers with one reaction and give optically pure spiro-cyclopropane derivatives 5a--5d which are difficult to obtain by routine methods. The synthetic method for 5a--5d was studied in detail and the new compounds were identified on the basis of their analytical data and spectroscopic data, such as [α]^(20),IR,~1H NMR,^(13)C NMR, MS and elementary analysis. The absolute configuration of the sprio [5-l-menthyloxy-3-bromo butyrolactocyclopropane-3″, 3′(4′-methyloxy-5′-menthyloxybutyrolactone)] (5a) was established by X-ray crystallography. The work can provide important synthetic strategy in synthesis of some new optically active spiro-cyclopropane analogues and some biologically active molecules with complex structure.展开更多
基金Supported by the Natural Science Foundation of Shaanxi Province,China(No.2009JM2001)the Innovation Foundation of Postgraduate Cultivation of Shaanxi Normal University,China(No.2008CXB009).
文摘An easy and efficient method for the synthesis of multisubstituted cyclopropane derivatives from electron-deficicent alkenes with 2-bromo-1,3-propanedione compounds was described.For this method,ethylα-cyanocinnamate derivatives 1 andβ,β-dicyanostyrene derivatives 4 can all smoothly reacted with 2-bromo-1,3-propanedione compounds 2 to afford the corresponding multisubstituted cyclopropane derivatives 3 and 5 in good to excellent yields(up to 100%)promoted by anhydrous K3PO4 in DMF at room temperature,respectively.A possible mechanism of this reaction was proposed.Structures of all the products were confirmed by ^1H NMR,^13C NMR and HRMS.
基金Project supported by the National Natural Science Foundation of China (Grant No. 29672004)
文摘Tandem asymmetric double Michael addition/internal nucleophilic substitution of the novel chiral source, 5-(l-menthyloxy)-3-bromo-2(5H)-furanone with nucleophilic alcohol compounds has been investigated. The tandem asymmetric reaction can afford four new stereogenic centers with one reaction and give optically pure spiro-cyclopropane derivatives 5a--5d which are difficult to obtain by routine methods. The synthetic method for 5a--5d was studied in detail and the new compounds were identified on the basis of their analytical data and spectroscopic data, such as [α]^(20),IR,~1H NMR,^(13)C NMR, MS and elementary analysis. The absolute configuration of the sprio [5-l-menthyloxy-3-bromo butyrolactocyclopropane-3″, 3′(4′-methyloxy-5′-menthyloxybutyrolactone)] (5a) was established by X-ray crystallography. The work can provide important synthetic strategy in synthesis of some new optically active spiro-cyclopropane analogues and some biologically active molecules with complex structure.
