Higher-order [10 + 2] cycloaddition of 2-alkylidene-1-indanones enables the dearomatization of 3-nitroindoles: access to polycyclic cyclopenta[b]indoline derivatives

The higher-order [10 + 2] cycloaddition of 3-nitroindoles and 2-alkylidene-1-indanones enables the dearomatization of 3-nitroindoles and affords a range of structurally diverse cyclopenta[ b ]indolines with excellent results.