Metal-catalyzed [2+2+1] cycloadditions of 1,3-dienes, allenes, and CO.

Article: Step economy is a preeminent goal of synthesis. [1] It influences the length, efficiency, cost, time, separation, and environmental impact of a synthesis. Step economy is favored by the use of single, serial, or multicomponent reactions that proceed in one operation with a great increase in target revelant complexity. The design or discovery of such reactions is thus critical to extending the practical reach of organic synthesis. Toward this end, we have directed effort at the identification of new metal-catalyzed reactions, especially those which are forbidden or difficult to achieve in the absence of a catalyst. This program has thus far produced several new two-, three-, and four-component reactions, including [4+4], [2] [4+2], [3] [5+2], [4] [6+2], [5] [5+2+1], [6] [2+2+1], [7]