Stereocontrol in nickel mediated syntheses of cyclobutabenzenes. The selective preparation of cis and trans derivatives of 7,8-dibromocyclobutabenzene
作者:Amnon Stanger、Alona Shachter、Roland Boese
DOI:10.1016/s0040-4020(97)10219-8
日期:1998.2
are substituted at the ortho and meta positions yield, upon applying nickel mediated cyclization conditions, the respective trans-7,8-dibromocyclobutabenzenes derivatives as major products. However, when the ortho substituent is an ester or an amide, a good stereochemical control can be achieved by running the reactions with or without the presence of phosphines. The bromineatom at the 7 position can