Brønsted Acid Catalyzed PhSe Transfer versus Radical Aryl Transfer: Linear Codimerization of Styrenes and Internal Olefins

Brønsted
acid p-TsOH·H2O-catalyzed
hydrovinylation of styrenes with internal olefins α-oxo ketene
dithioacetals was efficiently achieved in the presence of N-phenylselenophthalimide (N-PSP), regioselectively
affording Markovnikov phenylselenative hydrovinylation products through
PhSe transfer of the phenylseleno ketene dithioacetal intermediates.
Radical reduction of the resultant PhSe-alkyl-substituted ketene dithioacetals
with AIBN/n-Bu3SnH gave the corresponding anti-Markovnikov hydrovinylation products formally from
the linear codimerization of styrenes and the internal olefins.

在N-苯基硒邻苯二甲酰亚胺（N-phenylselenophthalimide，N-PSP）存在下，以布朗斯特酸（Brønsted acid）对甲苯磺酸一水合物（p-TsOH·H₂O）催化苯乙烯类化合物与内烯烃α-氧代烯酮二硫缩醛的氢乙烯基化反应可高效完成；反应通过苯基硒代烯酮二硫缩醛中间体的苯基硒转移过程，区域选择性地生成马氏规则（Markovnikov）型苯基硒代氢乙烯基化产物。采用偶氮二异丁腈（AIBN）/三丁基氢化锡（n-Bu₃SnH）对所得含苯基硒烷基取代的烯酮二硫缩醛进行自由基还原，可得到对应的反马氏规则（anti-Markovnikov）型氢乙烯基化产物，该产物形式上可看作苯乙烯与内烯烃经线性共二聚反应的产物。