Michael type reactions mediated by NbCl5.

Over the years researchers have been increasingly interested in the Michael addition, because this is one of the most useful reactions for the construction of carbon-carbon bonds, particularly in the synthesis of naturally occurring products and compounds with biological and pharmacological activity. We report here some experimental results involving NbCl5 mediated Michael addition followed by cyclization to bicyclic systems. Bicyclic compounds are traditionally synthesized through Diels Alder reactions. In this work, bicyclo[2.2.2]octan-2-ones have been synthesized using cross-conjugate dienes derived from cyclohexenones.