1α- and 1β-methyl agarofuran 1 and 2 were stereoselectively synthesized. the key intermediates being synthesized through stereoselective Robinson annulation.The conjugated double bond was redined in an improved way...1α- and 1β-methyl agarofuran 1 and 2 were stereoselectively synthesized. the key intermediates being synthesized through stereoselective Robinson annulation.The conjugated double bond was redined in an improved way. Alkylation of imine 7 with enone 8, 9, 10 was performed展开更多
Nor-ketoagarofuran (1), one of the furanoids isolated from grnd Oil, has been Synthesed in a preprative scale in high yield from olefin 3 in 3 steps. Reaction of norketoagarofuran (1) with CH3MgI afforded 4 (2), an an...Nor-ketoagarofuran (1), one of the furanoids isolated from grnd Oil, has been Synthesed in a preprative scale in high yield from olefin 3 in 3 steps. Reaction of norketoagarofuran (1) with CH3MgI afforded 4 (2), an another naturallyoccurring tetrahydrofuran derivative.展开更多
The structures of five metabolites (2-6) of agarofuran 1 were confirmed by synthesis. The configuration of the secondary hydroxyl in 7 was determined by Horeau抯 method. The configuration of C-2 in compound 4 and 5 ...The structures of five metabolites (2-6) of agarofuran 1 were confirmed by synthesis. The configuration of the secondary hydroxyl in 7 was determined by Horeau抯 method. The configuration of C-2 in compound 4 and 5 was determined by their stereochemistry and NMR.展开更多
A new synthetic route for α -agarofuran(1b) is described. Several agarofuran derivatives were synthesized in similar way. Derivative 1d was also synthesized in a novel way, in which the substitution at C-4 was perfor...A new synthetic route for α -agarofuran(1b) is described. Several agarofuran derivatives were synthesized in similar way. Derivative 1d was also synthesized in a novel way, in which the substitution at C-4 was performed quantitatively. An ideal condition for cyclization of diol 7 to agarofuran (1) was found.展开更多
Agarofuranoids with oxygen functions at C-1 and C-2 were synthesized by allylic oxidation. Ketone 2 gave compound 8 and 9 by Grignard reaction. The configuration of C-2 in 8 and 9 were identified by the CD spectroscop...Agarofuranoids with oxygen functions at C-1 and C-2 were synthesized by allylic oxidation. Ketone 2 gave compound 8 and 9 by Grignard reaction. The configuration of C-2 in 8 and 9 were identified by the CD spectroscopy of the benzoate 10.展开更多
Reduction of epoxides 1, 2, 3 with LAH and LAH/AlCl3 has been studied. The products of reduction with LAH were controlled by Steric and stereoelectronic effects. The reduction with LAH/AlCl3 seemed to involve an inter...Reduction of epoxides 1, 2, 3 with LAH and LAH/AlCl3 has been studied. The products of reduction with LAH were controlled by Steric and stereoelectronic effects. The reduction with LAH/AlCl3 seemed to involve an intermediate in which one aluminum ion was shared by both oxygen atoms from the epoxide and the tetrahydrofuran ring.展开更多
14-Nor-3-oxodihydroagarofuran (2) was prepared in high yield. From 2, derivatives12 and 13 were synthesized by Grignard addition. In order to identify the configuration of C-3 in compound 12 and 13, the sterospecific ...14-Nor-3-oxodihydroagarofuran (2) was prepared in high yield. From 2, derivatives12 and 13 were synthesized by Grignard addition. In order to identify the configuration of C-3 in compound 12 and 13, the sterospecific synthesis of compound 12 has been carried out in 5 steps from octalone (14).展开更多
One new sesquiterpene polyol eater named angulatin C was isolated from the root bark of Celastrus angulatus along with a known compound, angulatin B. Their structures were elucidated on the basis of spectral analysis.
Baker抯 yeast mediated reduction of optically active diketone is described. The two keto groups are efficiently dif-ferentiated and the ee value of the recovered material is considerably raised. It affords highly opti...Baker抯 yeast mediated reduction of optically active diketone is described. The two keto groups are efficiently dif-ferentiated and the ee value of the recovered material is considerably raised. It affords highly optically active key intermediates efficiently for the synthesis of natural polyhydroxylated agarofuran products.展开更多
文摘1α- and 1β-methyl agarofuran 1 and 2 were stereoselectively synthesized. the key intermediates being synthesized through stereoselective Robinson annulation.The conjugated double bond was redined in an improved way. Alkylation of imine 7 with enone 8, 9, 10 was performed
文摘Nor-ketoagarofuran (1), one of the furanoids isolated from grnd Oil, has been Synthesed in a preprative scale in high yield from olefin 3 in 3 steps. Reaction of norketoagarofuran (1) with CH3MgI afforded 4 (2), an another naturallyoccurring tetrahydrofuran derivative.
文摘The structures of five metabolites (2-6) of agarofuran 1 were confirmed by synthesis. The configuration of the secondary hydroxyl in 7 was determined by Horeau抯 method. The configuration of C-2 in compound 4 and 5 was determined by their stereochemistry and NMR.
基金This work was suppol-ted by the National Natural Science Foundation of China.
文摘A new synthetic route for α -agarofuran(1b) is described. Several agarofuran derivatives were synthesized in similar way. Derivative 1d was also synthesized in a novel way, in which the substitution at C-4 was performed quantitatively. An ideal condition for cyclization of diol 7 to agarofuran (1) was found.
基金the National Natural Science Foundation of China.
文摘Agarofuranoids with oxygen functions at C-1 and C-2 were synthesized by allylic oxidation. Ketone 2 gave compound 8 and 9 by Grignard reaction. The configuration of C-2 in 8 and 9 were identified by the CD spectroscopy of the benzoate 10.
基金the National Natural Science Foundation of China.
文摘Reduction of epoxides 1, 2, 3 with LAH and LAH/AlCl3 has been studied. The products of reduction with LAH were controlled by Steric and stereoelectronic effects. The reduction with LAH/AlCl3 seemed to involve an intermediate in which one aluminum ion was shared by both oxygen atoms from the epoxide and the tetrahydrofuran ring.
文摘14-Nor-3-oxodihydroagarofuran (2) was prepared in high yield. From 2, derivatives12 and 13 were synthesized by Grignard addition. In order to identify the configuration of C-3 in compound 12 and 13, the sterospecific synthesis of compound 12 has been carried out in 5 steps from octalone (14).
文摘One new sesquiterpene polyol eater named angulatin C was isolated from the root bark of Celastrus angulatus along with a known compound, angulatin B. Their structures were elucidated on the basis of spectral analysis.
基金Project supported by the National Natural Science Foundation of China (No. 20272021).
文摘Baker抯 yeast mediated reduction of optically active diketone is described. The two keto groups are efficiently dif-ferentiated and the ee value of the recovered material is considerably raised. It affords highly optically active key intermediates efficiently for the synthesis of natural polyhydroxylated agarofuran products.
