188982-49-2Relevant academic research and scientific papers
Probing for steric and electronic effects in diastereoselective dioxirane epoxidations compared to the oxygen transfer by peroxy acids
Adam, Waldemar,Paredes, Rodrigo,Smerz, Alexander K.,Veloza, L. Angela
, p. 547 - 551 (2007/10/03)
The spiro transition state for the oxygen transfer by dioxiranes is substantiated by the fact that no enhanced steric effects are observed when dioxiranes with alkyl groups of different size are employed, as manifested by the same (within the experimental error) diastereoselectivities in the epoxidation of 2-menthene and 1,3-dimethylcyclohexene for different dioxiranes. The π-facial selectivity (anti attack) in the epoxidation of the acetate and the methyl and trimethylsilyl ether derivatives of 2-cyclohexenol derives from steric interactions, whereas a pronounced electronic effect (electrostatic repulsion) is held responsible for the high anti selectivity of peroxides such as ascaridol and 3-hydroperoxycyclohexene. Quite generally, dioxiranes display only slightly higher diastereoselectivities than mCPBA in sterically controlled epoxidations of cycloalkenes. VCH Verlagsgesellschaft mbH, 1997.
Diastereoselectivity in the epoxidation of substituted cyclohexenes by dimethyldioxirane
Murray, Robert W.,Singh, Megh,Williams, Brian L.,Moncrieff, Hazel M.
, p. 1830 - 1841 (2007/10/03)
Three series of compounds based on the cyclohexene framework have been epoxidized by dimetbyldioxirane. A pronounced dependence of epoxide diastereoselectivity on substituent has been observed. In addition there is a solvent influence on this stereoselectivity. The results have been explained by invoking steric, H-bonding, and dipole - dipole influences on the epoxide stereochemistry.
