Nayana Joseph

Palladium catalyzed reaction of ortho-functionalized aryl iodides with bicyclic hydrazines: facile route toward heteroannulated cyclopentenes and azabicycles

Abstract A palladium catalyzed tandem protocol for the synthesis of cyclopentene fused heterocycles from diazabicyclic alkenes and ortho -functionalized aryl iodides has been elaborated. This tandem protocol was utilized for the synthesis of a number of cyclopentene fused dihydrobenzofurans and indolines. The reaction can be tuned toward the formation of either 3,4-disubstituted cyclopentenes or cyclopentene fused heterocycles by careful manipulation of the reaction parameters. The reaction was also extended to bicyclic alkenes derived from fulvene, which resulted in the heteroannulation of the azabicyclic system.

An exclusive approach to 3,4-disubstituted cyclopentenes and alkylidene cyclopentenes via the palladium catalyzed ring opening of azabicyclic olefins with aryl halides

A simple and efficient method for the stereoselective ring opening of bicyclic hydrazines with various aryl halides under palladium catalysis has been elaborated. The reactions afforded trans-3,4-disubstituted cyclopentenes or alkylidene cyclopentenes in good to excellent yields. By taking advantage of multiple points of functionalization in the synthesized trans-3-phenyl-4-hydrazino-cyclopentene, we have synthesized the antidepressant Cypenamine (trans-2-phenylcyclopentylamine).

CCDC 876343: Experimental Crystal Structure Determination

Related Article: Jubi John, Rani Rajan, S. Sarath Chand, Praveen Prakash, Nayana Joseph, Eringathodi Suresh, K.V. Radhakrishnan|2013|Tetrahedron|69|152|doi:10.1016/j.tet.2012.10.053

Trapping the π-AllylpalladiumIntermediate from Fulvene-Derived Azabicyclic Olefin withSoft Nucleophiles

A facile method for the synthesis of a new class of disubstituted alkylidenecyclopentenes has been introduced. The methodology involves the palladium-catalyzed ring opening of pentafulvene-derived bicyclic hydrazines with phenols and active methylene compounds, furnishing 1,4-disubstituted alkylidenecy-clopentenes in good yield. The utility of multiple points of functionalization was effectively demonstrated by the synthesis of a substituted cyclopentanone and 2-hydrazinofulvene.