2-Alkenyl p-tolyl sulfones were converted into the corresponding 3-acetoxy(or chloro)-1-alkenyl p-tolyl sulfones via π-allylpalladiumcomplexes which reacted regiospecifically with a nucleophile such as acetate anion or chloride anion in the presence of Cu(II).
2-烯基对甲苯基砜通过 π-烯丙基钯配合物转化为相应的 3-乙酰氧基(或氯)-1-烯基对甲苯基砜,该配合物在 Cu 存在下与乙酸根阴离子或氯阴离子等亲核试剂发生区域特异性反应(二)。
Stereochemistry of the Conversion of γ-Substituted (<i>E</i>)-Vinylsulfones to the Corresponding Allylsulfones. Determination of the Relative Degree of “Syn-Effect”
The relative degree of “syn-effect” for the γ-substituted vinylsulfones in their conversion to the corresponding allylsulfones with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) was determined by observing E/Z ratios of the resulting allylsulfones as follows: CH3O– ≥ AcO– > CH3– > –CH2– >> t-Bu– and Ph–.
The synthesis of gamma-functionalized vinyl sulfones 3 have been carried out directly starting from dibromides 2 derived from allyl sulfones 1 by reaction with different nucleophiles. The process is stereoselective affording compounds 3 with E configuration except in the case of methallylic derivatives. The regioisomeric gamma-functionalized allyl sulfones 4 were obtained from dibromides 2 or from vinyl sulfones 3, with Z configuration, except when triphenylphosphine was used as nucleophile, in this case the corresponding (E)-vinylphosphonium bromide 4al was obtained.
Palladium(II)-assisted conversion of a 2-alkenyl sulfone into a 3-acetoxy(or chloro)-1-alkenyl sulfone
作者:Katsuyuki Ogura、Nobuhiro Shibuya、Hirotada Iida
DOI:10.1016/s0040-4039(01)90366-1
日期:1981.1
INOMATA, KATSUHIKO;HIRATA, TAKAKI;SUHARA, HIROSHI;KINOSHITA, HIDEKI;KOTAK+, CHEM. LETT.,(1988) N2, C. 2009-2012