Organocatalytic Enantioselective [8+4] Cycloadditions of Isobenzofulvenes for the Construction of Bicyclo[4.2.1]nonanes.

Main observation and conclusion: The [8+4] cycloaddition of indene‐2‐carbaldehydes with indole‐2,3‐quinodimethanes and pyrrolidone‐3,4‐dienes is described, affording indole and pyrrolidone annulated bicyclo[4.2.1]nonanes in a highly peri‐, diastereo‐, and enantioselective fashion in the presence of a secondary amine catalyst. This reaction, which proceeds through catalytically generated isobenzofulvenes, represents the first asymmetric version of high‐order [8+4] cycloaddition. [ABSTRACT FROM AUTHOR]