Lewis Acid Catalyzed Tandem Polycyclization of Internal Alkynols and Vinyl Azides

A novel Lewis acid
catalyzed tandem cyclization reaction of internal
alkynols and vinyl azides has been achieved to afford a series of
products containing a pyran-based indeno­[1,2-c]­isochromene
scaffold in moderate to high yields. This tandem polycyclization protocol
provides a straightforward entry to construct the complex polycyclic
skeleton through cycloisomerization, formal [4 + 2] cycloaddition,
and an elimination process.

本工作实现了一类新型路易斯酸（Lewis acid）催化的内炔醇与乙烯基叠氮（vinyl azides）的串联环化反应，可得到一系列含有吡喃并茚并[1,2-c]异色烯骨架的产物，产率处于中等到较高水平。该串联多环化策略可通过环异构化、形式[4+2]环加成与消除过程，为复杂多环骨架的构建提供一条简洁高效的途径。