Tandem reaction of α-hypervalent iodo functionalized phosphonium and arsonium ylides as umpolung reagents
作者:Zhi-Zhen Huang、Xiao-Chun Yu、Xian Huang
DOI:10.1016/s0040-4039(02)01503-4
日期:2002.9
α-Hypervalent iodo functionalized phosphonium and arsonium ylides 2 can be used as umpolung ylides to react with nucleophiles to give α-heteroatom substituted ylides 4 in good yields. A tandem sequence of nucleophilic substitution then Wittig reaction occurs smoothly to form (Z)-α-halo-α,β-unsaturated esters 6, stereoselectively, in moderate to excellent yields.
Synthesis of α-phenylseleno-α,β-unsaturated esters by Wittig-type reactions. Studies on the Diels–Alder reaction
作者:Claudio C. Silveira、Marta R.S. Nunes、Elson Wendling、Antonio L. Braga
DOI:10.1016/s0022-328x(00)00685-9
日期:2001.3
anion and ethoxycarbonyl(phenylselenenyl)methylidene(triphenyl)phosphorane with aliphatic and aromaticaldehydes. The α-phenylseleno unsaturated esters were obtained as mixtures of E/Z-isomers in medium to good yields and in moderate yields, respectively. α-Phenylselenenyl acrylate was used as dienophile in a Diels–Alder reaction. On reaction with isoprene only the para isomer was obtained while reaction