Regioselective synthesis of amino- and nitroarenes based on [3+3] cyclocondensations of 1,3-bis(silyloxy)-1,3-butadienes

Functionalized amino- and nitro-substituted biaryls and dibenzo[b,d]pyrid-6-ones (6(5H)-phenanthridinones) were prepared by [3+3]cyclocondensation of 1,3-bis(trimethylsilyloxy)-1,3-butadienes with nitro-substituted 1-aryl-1-silyloxy-1-en-3-ones and subsequent hydrogenation. 4-Nitro- and 4-aminophenols were prepared based on formal [3+3] cyclizations of 1,3-bis(trimethylsilyloxy)-1,3-butadienes with 3-ethoxy-2-nitro-2-en-1-ones.