A [5+1] annulation strategy for the synthesis of multifunctional biaryls andp-teraryls from 1,6-Michael acceptor ketene dithioacetals

A new type of ketene dithioacetal, 2-(3,3-bis-methylsulfanyl-1-arylallylidene)malononitriles containing 1,4 and 1,6-Michael acceptors, were synthesized to study their reactivity for the synthesis of a new molecular entity. We report a [5 + 1] annulation strategy for the construction of multifunctional biaryls andp-teraryls by the selection of a suitable nucleophilic source. The reaction ofp-nitrotoluene with 2-(3,3-bis-methylsulfanyl-1-aryl-allylidene)malononitriles under basic conditions producesp-teraryls in good yields, while the use of nitroethane as the nucleophile source provides functionalized biaryls through cyclization, followed by denitration. This reaction requires mild conditions and exhibits good functional group tolerance.