Substitution Reactions in the β-Styryl and Phenylethynyl Systems

Article abstract of DOI:10.1021/jo00269a018

Substitution for Q in the systems PhCH=CHQ, Ph2C=CHQ, and PhCCQ can occur by a free-radical chain mechanism where the attacking radical is alkyl (Q = HgX, Bu3Sn, PhSO2, PhSO, PhS, Cl, Br, I) or (EtO)2PO^. (Q = HgX, Bu3Sn, I).The Q^. radicals formed by β-elimination can generate t-Bu^. or (EtO)2PO^. by reaction with t-BuHgCl, Hg2, ClHg or by electron transfer between ^.HgCl and (EtO)2PO^-.With Q = PhS or PhSO2, relative reactivity data indicates that the free radical addition-elimination sequence occurs for t-BuLi at 0 or 45 deg C andthat this process may also be involved in reactions of t-BuMgCl or tert-butyl cuprates with some of the substrates.Ionic reaction of (EtO)2PO^- with the three substrates with Q = PhSO2 or halogen are examined.With Q = PhSO2, PhCHCH2P(O)(OEt)2, Ph2C=CHP(O)(OEt)2, and PhCCP(O)(OEt)2 are formed in good yield.