Regiochemical control in intramolecular cyclizations of 2,3-epoxysulfides mediated by solvent effects
作者:Meenakshi Sivakumar、Babak Borhan
DOI:10.1016/s0040-4039(03)01210-3
日期:2003.7
The regioselectivity of cyclization in methylene-interrupted epoxydiols with a thiophenyl ether group adjacent to the epoxide can be controlled by the appropriate choice of reaction conditions. Thus, while the 5-exo mode of cyclization is observed under protic conditions with polar solvents, the intermediacy of an episulfonium ion generated in non-polar solvents lead to a regioisomeric THF product
环化在与相邻的环氧化物噻吩醚基的亚甲基间断epoxydiols区域选择性可以通过反应条件的适当选择被控制。因此,尽管在质子条件下用极性溶剂观察到环化的5- exo模式,但在非极性溶剂中产生的epi硫离子的中间体导致区域异构的THF产物。