Dearomatization of 3‐Nitroindoles with Highly γ‐Functionalized Allenoates in Formal (3+2) Cycloadditions
Résumé
3‐Nitroindoles are easily reacted with highly substituted γ‐allenoates in the presence of a commercially available phosphine catalyst. For instance, allenoates derived from biomolecules such as amino and deoxycholic acids are combined for the first time with 3‐nitroindole. The corresponding dearomatized (3+2) tricyclic cycloadducts are obtained as α‐regioisomers exclusively. DFT computations shed light on this multi‐step reaction mechanism and on the selectivities observed in the sequence.