Friedel-Crafts Cyclialkylations of Some Epoxides

Article abstract of DOI:10.1021/jo00163a001

Several arylalkyl epoxides (1-9) were investigated for cyclialkylation reactions.Cyclialkylation to form six-membered rings was observed (up to 91 percent isolated yields) at secondary but not at primary epoxide positions.Cyclialkylation was not observed with 4-phenyl-1,2-epoxybutane, but a m-methoxy substituent did promote ring closure to the primary position in moderate yield.Cyclialkylation to seven-membered rings occurred at a secondary position in reasonable yields; less rearrangement occured with the epoxide system than with analogous alkylating agents such as phenylalk yl alcohols.Reduced skeletal rearrangement is characteristic of cyclization reactions that occur with epoxides and suggests that the epoxide serves to moderate electrophilic reactivity.Cyclialkylation to form five-membered rings was not observed with epoxides that were capable of ring-opening at primary or secondary positions.