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
The title compound, spiro[1-bromo-4-l-menthyloxy-5-oxo-6-oxa-bicyclo[3.1.0]-hexane-2,2-3-(16-methoxyacetatyl-4-l-menthyloxybutyrolactone)] 1, was obtained via tandem asymmetric double Michael addition/internal nucleop...The title compound, spiro[1-bromo-4-l-menthyloxy-5-oxo-6-oxa-bicyclo[3.1.0]-hexane-2,2-3-(16-methoxyacetatyl-4-l-menthyloxybutyrolactone)] 1, was obtained via tandem asymmetric double Michael addition/internal nucleophilic substitution of the chiral synthon, 5-l-menthyloxy-3-bromo-2-(5H)-furanone 2 with methoxy α-chloroacetate as a nucleophile under mild conditions, and structurally determined by single-crystal X-ray diffraction. Crystal data: C31H47BrO9, Mr = 643.60, orthorhombic, space group P212121, a = 9.6564(7), b = 14.8994(11), c = 23.6771(17) , V = 3406.5(4) 3, Z = 4, Dc = 1.255 g/cm3, λ(MoKα) = 0.71073 , μ = 1.254 mm-1 and F(000) = 1360. The structure was refined to R = 0.0324 and wR = 0.0737 for 5123 observed reflections (I > 2σ(I)). The crystallographic results of molecule 1 show that the interesting reaction of 2 with methoxy α-chloroacetate, in the usual manner, gave the spiro-cyclopropane skeleton with O-linked derivative containing multiple stereogenic centers 1 rather than the expected C-linked derivative.展开更多
Phenylglycine 1 as a representative of natural resourceful a-amino acid was modified by reduction and protection of functional group to afford the amino alcohol as a chiral building block 3. A new chiral compound, the...Phenylglycine 1 as a representative of natural resourceful a-amino acid was modified by reduction and protection of functional group to afford the amino alcohol as a chiral building block 3. A new chiral compound, the chiral building block/spiro-cyclopropane derivative containing four stereogenic centers, compound 7, has been obtained in 52% yield with de≥98% via the tandem double Michael addition/internal nucleophilic substitution under mild condition of 5-l-menthyloxy-3-bromo-2-(5H)-furanone 4 with the nucleophilic reagent, the amino alcohol 3. The new chiral compound 7 is identified on the basis of its analytical data and spectroscopic data, such as UV, IR, 1H NMR, 13C NMR, MS and elementary analysis. The absolute configuration of the interesting spiro-cyclopropanes 7 was established by X-ray crystallography. This result can provide new route and method for the introduction of chiral building block and the important synthetic strategy in synthesis of some complex molecules containing展开更多
The synthetic method of the novel chiral synthon, 5-/-menthyloxy-3-chloro-2-(5H)-furanone 5a and its application in asymmetric reactions were investigated. 5a is easily obtained in highly optical purity, and acts as a...The synthetic method of the novel chiral synthon, 5-/-menthyloxy-3-chloro-2-(5H)-furanone 5a and its application in asymmetric reactions were investigated. 5a is easily obtained in highly optical purity, and acts as a stable acceptor of Michael addition with oxygen nucleophiles in tandem double Michael addition / internal nucieophilic substitution to offer the spiro-cyclopropane derivative containing four stereogenic centers 8, which it is difficult to obtain by routine methods. The synthetic methods for 5a and 8 are reported in detail and the new compounds are identified on the basis of their analytical data and spectroscopic data, such as UV, IR, H NMR,13 C NMR, MS and elementary analysis. The absolute configuration of the interesting spiro-cyclopropanes, spiro [1-chloro-4-(/-menthyloxy)-5-oxo-6-oxa-biscyclo[3.1.0]hexane-2,3i(4’-/-menthyloxy-5’-/-menthyloxy- butyrolactone)] 8 was established by X-ray crystallography. This result can provide important synthetic strategy in synthesis of some complex展开更多
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.
文摘The title compound, spiro[1-bromo-4-l-menthyloxy-5-oxo-6-oxa-bicyclo[3.1.0]-hexane-2,2-3-(16-methoxyacetatyl-4-l-menthyloxybutyrolactone)] 1, was obtained via tandem asymmetric double Michael addition/internal nucleophilic substitution of the chiral synthon, 5-l-menthyloxy-3-bromo-2-(5H)-furanone 2 with methoxy α-chloroacetate as a nucleophile under mild conditions, and structurally determined by single-crystal X-ray diffraction. Crystal data: C31H47BrO9, Mr = 643.60, orthorhombic, space group P212121, a = 9.6564(7), b = 14.8994(11), c = 23.6771(17) , V = 3406.5(4) 3, Z = 4, Dc = 1.255 g/cm3, λ(MoKα) = 0.71073 , μ = 1.254 mm-1 and F(000) = 1360. The structure was refined to R = 0.0324 and wR = 0.0737 for 5123 observed reflections (I > 2σ(I)). The crystallographic results of molecule 1 show that the interesting reaction of 2 with methoxy α-chloroacetate, in the usual manner, gave the spiro-cyclopropane skeleton with O-linked derivative containing multiple stereogenic centers 1 rather than the expected C-linked derivative.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 29672004).
文摘Phenylglycine 1 as a representative of natural resourceful a-amino acid was modified by reduction and protection of functional group to afford the amino alcohol as a chiral building block 3. A new chiral compound, the chiral building block/spiro-cyclopropane derivative containing four stereogenic centers, compound 7, has been obtained in 52% yield with de≥98% via the tandem double Michael addition/internal nucleophilic substitution under mild condition of 5-l-menthyloxy-3-bromo-2-(5H)-furanone 4 with the nucleophilic reagent, the amino alcohol 3. The new chiral compound 7 is identified on the basis of its analytical data and spectroscopic data, such as UV, IR, 1H NMR, 13C NMR, MS and elementary analysis. The absolute configuration of the interesting spiro-cyclopropanes 7 was established by X-ray crystallography. This result can provide new route and method for the introduction of chiral building block and the important synthetic strategy in synthesis of some complex molecules containing
文摘The synthetic method of the novel chiral synthon, 5-/-menthyloxy-3-chloro-2-(5H)-furanone 5a and its application in asymmetric reactions were investigated. 5a is easily obtained in highly optical purity, and acts as a stable acceptor of Michael addition with oxygen nucleophiles in tandem double Michael addition / internal nucieophilic substitution to offer the spiro-cyclopropane derivative containing four stereogenic centers 8, which it is difficult to obtain by routine methods. The synthetic methods for 5a and 8 are reported in detail and the new compounds are identified on the basis of their analytical data and spectroscopic data, such as UV, IR, H NMR,13 C NMR, MS and elementary analysis. The absolute configuration of the interesting spiro-cyclopropanes, spiro [1-chloro-4-(/-menthyloxy)-5-oxo-6-oxa-biscyclo[3.1.0]hexane-2,3i(4’-/-menthyloxy-5’-/-menthyloxy- butyrolactone)] 8 was established by X-ray crystallography. This result can provide important synthetic strategy in synthesis of some complex
