Nucleophilic Vinylic Substitutions of (<i>Z</i>)-(β-Haloalkenyl)phenyliodonium Salts with Sodium Benzenesulfinate: First Evidence of a Michael Addition of Nucleophiles to Alkenyliodonium Salts at the C<sub>β</sub> Atom
作者:Masahito Ochiai、Yutaka Kitagawa、Mika Toyonari、Koji Uemura、Kunio Oshima、Motoo Shiro
DOI:10.1021/jo970735v
日期:1997.11.1
alkenyl(phenyl)iodonium salts at the C(beta) atom is reported here for the first time. Nucleophilic vinylic substitutions of (Z)-(beta-chloroalkenyl)- 2b and (Z)-(beta-bromoalkenyl)iodonium tetrafluoroborates 3b with sodium benzenesulfinate in THF afforded stereoselectively (Z)-1,2-bis(benzenesulfonyl)alkene 5b with retention of configuration. Intermediate formation of (Z)-(beta-(benzenesulfonyl)alkenyl)iodonium salt
本文首次报道了亲核试剂在Cβ原子上链烯基(苯基)碘鎓盐迈克尔加成的证据。(Z)-(β-氯烯基)-2b和(Z)-(β-溴烯基)碘化四氟硼酸钾3b在THF中用苯亚磺酸钠进行亲核乙烯基取代,得到立体选择性的(Z)-1,2-双(苯磺酰基)烯烃5b保留配置。通过(1)H NMR实验在CDCl(3)中确定在这些反应中的中间形成(Z)-(β-(苯磺酰基)烯基)碘盐9b。(Z)-9b的形成涉及迄今未观察到的苯磺酸亚砜阴离子在Cβ原子处链烯基碘鎓盐的迈克尔加成反应,然后进行卤素挤出。(Z)-和(E)-双砜5b的立体异构体混合物的形成,