@article { ISI:000306670200022, title = {InCl3-mediated addition of indole to isatogens: an expeditious synthesis of 13-deoxy-isatisine A}, journal = {Chemistry-A European Journal}, volume = {18}, number = {31}, year = {2012}, month = {JUL}, pages = {9601-9611}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

A strategy directed towards the total synthesis of isatisine A that involves several late-stage metal-catalyzed transformations that address the key carboncarbon and carbonheteroatom bond formations has been developed. As a part of this strategy, methods for the addition of indoles to isatogens that lead selectively to either 2,2-disubstituted N-hydroxyindolin-3-one or 2,2-disubstituted indolin-3-one compounds have been developed by employing InCl3 as a catalyst or as the reagent. The present methods provide the first examples of the additions of indoles to the isatogen nucleus. To demonstrate its viability, the synthesis of 13-deoxy-isatisine A has been completed in ten steps from a known and easily available lactone.

}, keywords = {indium, indoles, isatogens, Natural products, Total synthesis}, issn = {0947-6539}, doi = {10.1002/chem.201103604}, author = {Kumar, Chepuri V. Suneel and Puranik, Vedavati G. and Ramana, Chepuri V.} } @article { ISI:000342117600019, title = {Tuning the regioselectivity of gold-catalyzed internal nitroalkyne redox: a cycloisomerization and [3+2]-cycloaddition cascade for the construction of spiro-pseudoindoxyl skeleton}, journal = {Organic Letters}, volume = {16}, number = {18}, year = {2014}, month = {SEP}, pages = {4766-4769}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

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.

}, issn = {1523-7060}, doi = {10.1021/ol502213w}, author = {Kumar, Chepuri V. Suneel and Ramana, Chepuri V.} } @article { ISI:000356845000002, title = {Ru-catalyzed redox-neutral cleavage of the N-O bond in isoxazolidines: isatogens to pseudoindoxyls via a one-pot [3+2]-cycloaddition/N-O cleavage}, journal = {Organic Letters}, volume = {17}, number = {12}, year = {2015}, month = {JUN}, pages = {2870-2873}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

A novel metal-catalyzed oxygen atom transfer reaction onto olefins is reported. By taking isatogens as substrates, a one-pot [3 + 2]-cycloaddition of nitrone with olefins followed by the Ru-catalyzed redox-neutral N-O bond cleavage of intermediate isoxazolidine has been executed as a simple method for the synthesis of 2,2-disubstituted pseudoindoxyls.

}, issn = {1523-7060}, doi = {10.1021/acs.orglett.5b00837}, author = {Kumar, Chepuri V. Suneel and Ramana, Chepuri V.} }