Tuning the Regioselectivity of Gold-Catalyzed Internal Nitroalkyne Redox: A Cycloisomerization and [3 + 2]-Cycloaddition Cascade for the Construction of spiro-Pseudoindoxyl Skeleton
journal contributionposted on 19.09.2014, 00:00 by Chepuri V. Suneel Kumar, Chepuri V. Ramana
A simple domino process for the construction of the tricyclic core present in the spiro-pseudoindoxyl natural products has been developed. This involves two intramolecular events: the Au-catalyzed nitroalkyne redox leading to isatogen and its subsequent [3 + 2]-cycloaddition with a suitably positioned olefin. The option to modulate the size of the spiro-annulated ring, which is an important variable in this class of natural products, has been explored. Overall, this process molds a linear precursor into a tricyclic system with complete step, atom, and redox economy.