Gold-Catalyzed Dearomative Spirocyclization of <i>N</i>-Aryl Alkynamides for the Synthesis of Spirolactams
作者:Taylor L. Vacala、Paul R. Carlson、Asa Arreola-Hester、Chloé G. Williams、Evana W. Makhoul、Paul A. Vadola
DOI:10.1021/acs.joc.7b03125
日期:2018.2.2
A catalytic redox-neutral method for the synthesis of spirolactams proceeding through the dearomative spirocyclization of N-aryl alkynamides is reported. In contrast to stoichiometric activating agents employed for related transformations, we show that the use of 5 mol % of Au(PPh3)Cl and AgOTf in dichloroethane at 50–80 °C leads to selective spirocyclization, furnishing the products in yields of 35–87%
报道了通过N-芳基炔酰胺的脱芳香螺环化进行的合成螺内酰胺的催化氧化还原中性方法。与用于相关转化的化学计量活化剂相比,我们表明在50–80°C的二氯乙烷中使用5 mol%的Au(PPh 3)Cl和AgOTf可导致选择性螺环化,提供的产品收率为35–80。 87%。反应的底物范围是好的,给电子基团和吸电子基团在芳烃环的周围是可容忍的,并且在酰胺氮上也可被取代。该段的身份芳烃环上的-烷氧基基团是实现选择性环化的途径的关键,该环化是通过其他机制途径实现的。虽然对-甲氧基的存在导致痕量的所需螺内酰胺,但是对-叔丁氧基或对羟基底物类似物以高收率和高选择性提供了螺内酰胺。