Asymmetric Copper-Catalyzed [2,3]-Sigmatropic Rearrangements of Alkyl- and Aryl-Substituted Allyl Sulfides
摘要:
The asymmetric copper-catalyzed generation and subsequent [2,3]-sigmatropic rearrangement of sulfur ylides is strongly dependent on the structure of the starting allyl sulfide. A series of alkyl and aryl substituted allyl sulfides (2a-i) were reacted with ethyl diazoacetate in the presence of copper triflate (CuOTf) and a C-2-symmetric bis-oxazoline ligand (5a-c). The degree of asymmetric induction ranged from 2.8% for allyl methyl sulfide (2a) to 60% for (1S,2S,5R)-(+)-allyl menthyl sulfide (2d). The enantioselectivity of the reactions was also dependent on the electronic nature of the sulfide; allyl phenyl sulfide (2e) gave a 14% ee, whereas allyl p-methoxyphenyl sulfide (2i) produced only an 8% ee. The stereochemistry of 2d and (1R,2S,5R)-(+)-allyl menthyl sulfide (7) was assigned on the basis of NMR spectroscopic experiments.
Rotational isomerism in N-(N-heteroaryl)arenesulphenamides
作者:Robert S. Atkinson、Brian D. Judkins、Bhalchandra Patwardhan
DOI:10.1039/p29790001490
日期:——
N-(1,2-Dihydro-2-oxoquinolin-1-yl)-N-(1-methylallyl)-4-chlorobenzenesulphenamide (5) has previously been isolated in two stereoisomeric forms. From examination of a number of analogues of (5), it is concluded that the phenomenon which allows isolation of these stereoisomers is restricted rotation around the N–N bond.
Asymmetric Copper-Catalyzed [2,3]-Sigmatropic Rearrangements of Alkyl- and Aryl-Substituted Allyl Sulfides
作者:Douglas W. McMillen、Norbert Varga、Beth Ann Reed、Claudia King
DOI:10.1021/jo991842n
日期:2000.4.1
The asymmetric copper-catalyzed generation and subsequent [2,3]-sigmatropic rearrangement of sulfur ylides is strongly dependent on the structure of the starting allyl sulfide. A series of alkyl and aryl substituted allyl sulfides (2a-i) were reacted with ethyl diazoacetate in the presence of copper triflate (CuOTf) and a C-2-symmetric bis-oxazoline ligand (5a-c). The degree of asymmetric induction ranged from 2.8% for allyl methyl sulfide (2a) to 60% for (1S,2S,5R)-(+)-allyl menthyl sulfide (2d). The enantioselectivity of the reactions was also dependent on the electronic nature of the sulfide; allyl phenyl sulfide (2e) gave a 14% ee, whereas allyl p-methoxyphenyl sulfide (2i) produced only an 8% ee. The stereochemistry of 2d and (1R,2S,5R)-(+)-allyl menthyl sulfide (7) was assigned on the basis of NMR spectroscopic experiments.