The stereoselective synthesis of 2-chloro-4-substituted-phenyl-5,5-dimethyl-1,3,2-dioxaphosphorinan-2-(thi)ones is described. Only single trans-isomers were obtained when 1-substituted-phenyl-2,2-dimethyl-1,3-propaned...The stereoselective synthesis of 2-chloro-4-substituted-phenyl-5,5-dimethyl-1,3,2-dioxaphosphorinan-2-(thi)ones is described. Only single trans-isomers were obtained when 1-substituted-phenyl-2,2-dimethyl-1,3-propanediols (1) reacted with POCl3. But the stereoselectivity of cyclization reaction between (1) and PSCl3 depended greatly upon the reaction condition. The configurational assignments and the ratio of cis-/trans- diastereoisomers of the products were performed on the basis of (HNMR)-H-1, (PNMR)-P-31 and IR spectra and confirmed by X-ray diffraction analyses.展开更多
The reaction of cis- 2- chloro- 4- phenyl- 5, 5- dimethyl- 1, 3. 2-dioxaghosghor inan-2- thione (Ⅰ) with methoxide or phenoxide at room temperatute takes place with retent ion of configuration. while refluxing cis- ...The reaction of cis- 2- chloro- 4- phenyl- 5, 5- dimethyl- 1, 3. 2-dioxaghosghor inan-2- thione (Ⅰ) with methoxide or phenoxide at room temperatute takes place with retent ion of configuration. while refluxing cis- (1) and methoxide in methanol, gartial isomerization of cis-thioghosphate (2) to its trans isomer occursand an acyclic intermediate (3) is found to be involved in this grocess展开更多
The metaphosphate anion, PO_3, was detected in the negative-ion chemicalionization mass spectra of 2,6,7-trioxa-1-phospbabicyclo[2.2. 2] octane-1-oxides.
Trans-2,2-dimethyl-3-(2,2-dichloroethenyl)cyclopropanecarbonyl chloride, which is animportant intermediate for insecticides, is obtained by isomerization of the cis/trans-mixture with4- (N,N-dimethylamino) pyridine (D...Trans-2,2-dimethyl-3-(2,2-dichloroethenyl)cyclopropanecarbonyl chloride, which is animportant intermediate for insecticides, is obtained by isomerization of the cis/trans-mixture with4- (N,N-dimethylamino) pyridine (DMAP) in the presence or absence of halogen compounds ingood yield.展开更多
Acylation of 5-methyl-3-hydroxyisoxazole (1) with 3-substituted cyclopropanecarboxylic chlorides (3) in the presence of triethylamine (TEA) in acetonitrile yields predominantly O-acylated products (4).The N-acyl isome...Acylation of 5-methyl-3-hydroxyisoxazole (1) with 3-substituted cyclopropanecarboxylic chlorides (3) in the presence of triethylamine (TEA) in acetonitrile yields predominantly O-acylated products (4).The N-acyl isomers (5) are afforded regiospecifically using trimethylsilyl ether of 3-hydroxyisoxazole (2).展开更多
The stereochemistry of thionation reaction of 2 -substituted 4 -aryl- 5, 5 dimethyl - 1. 3. 2 -dioxaphosphorian-ones 1a-r with Lautssen's reagent (LR ) was reported in this paPer. The results indicated that the th...The stereochemistry of thionation reaction of 2 -substituted 4 -aryl- 5, 5 dimethyl - 1. 3. 2 -dioxaphosphorian-ones 1a-r with Lautssen's reagent (LR ) was reported in this paPer. The results indicated that the thionation reaction of LR proceeded predominantly with retention of configuration.The mechanism leading to retention was proposed by assuming a cyclic pentacoordinated intermidiate.展开更多
文摘The stereoselective synthesis of 2-chloro-4-substituted-phenyl-5,5-dimethyl-1,3,2-dioxaphosphorinan-2-(thi)ones is described. Only single trans-isomers were obtained when 1-substituted-phenyl-2,2-dimethyl-1,3-propanediols (1) reacted with POCl3. But the stereoselectivity of cyclization reaction between (1) and PSCl3 depended greatly upon the reaction condition. The configurational assignments and the ratio of cis-/trans- diastereoisomers of the products were performed on the basis of (HNMR)-H-1, (PNMR)-P-31 and IR spectra and confirmed by X-ray diffraction analyses.
文摘The reaction of cis- 2- chloro- 4- phenyl- 5, 5- dimethyl- 1, 3. 2-dioxaghosghor inan-2- thione (Ⅰ) with methoxide or phenoxide at room temperatute takes place with retent ion of configuration. while refluxing cis- (1) and methoxide in methanol, gartial isomerization of cis-thioghosphate (2) to its trans isomer occursand an acyclic intermediate (3) is found to be involved in this grocess
文摘The metaphosphate anion, PO_3, was detected in the negative-ion chemicalionization mass spectra of 2,6,7-trioxa-1-phospbabicyclo[2.2. 2] octane-1-oxides.
文摘Trans-2,2-dimethyl-3-(2,2-dichloroethenyl)cyclopropanecarbonyl chloride, which is animportant intermediate for insecticides, is obtained by isomerization of the cis/trans-mixture with4- (N,N-dimethylamino) pyridine (DMAP) in the presence or absence of halogen compounds ingood yield.
文摘Acylation of 5-methyl-3-hydroxyisoxazole (1) with 3-substituted cyclopropanecarboxylic chlorides (3) in the presence of triethylamine (TEA) in acetonitrile yields predominantly O-acylated products (4).The N-acyl isomers (5) are afforded regiospecifically using trimethylsilyl ether of 3-hydroxyisoxazole (2).
文摘The stereochemistry of thionation reaction of 2 -substituted 4 -aryl- 5, 5 dimethyl - 1. 3. 2 -dioxaphosphorian-ones 1a-r with Lautssen's reagent (LR ) was reported in this paPer. The results indicated that the thionation reaction of LR proceeded predominantly with retention of configuration.The mechanism leading to retention was proposed by assuming a cyclic pentacoordinated intermidiate.
