[5+1] Annulation strategy for the synthesis of multifunctional biaryls and p-teraryls from 1,6-Michael acceptor ketene dithioacetals

A new ketenedithioacetal, 2-(3,3-bis-methylsulfanyl-1-arylallylidene)malononitriles containing 1,4 and 1,6-Michael acceptor was synthesized to study their reactivity for the synthesis of new molecular entity. We are reporting [5+1] annulation strategy for the construction of multifunctional biaryls and p-teraryls by selection of suitable nucleophile source. The reaction of p-nitrotoluene with 2-(3,3-bis-methylsulfanyl-1-aryl-allylidene)-malononitriles under basic conditions provides p-teraryls in good yields, while use of nitroethane as nucleophile source provides functionalized biaryls through cyclization followed by denitration. The reaction requires mild condition and exhibit good functional group tolerance. The compounds are well characterized by spectroscopic data and single crystal X-ray.