Addition of Diazoalkanes to Enynes Promoted by a Ruthenium Catalyst: Simple Synthesis of Alkenyl Bicyclo[3.1.0]hexane Derivatives

International audience; [Cp*RuCl(cod)] (Cp * =C5Me5, cod=cyclooctadiene) promotes the reaction of 1,6- enynes with an excess of diazoalkane in dioxane in one step to afford selectively 1-alkenyl bicyclo[3.1.0]hexane derivatives (see scheme, X=O, NTs; Y=CO2Et; R1=H, Me; R2=H; Ts=p-toluenesulfonyl). This novel reaction involves the stereoselective formation of three CC bonds and a cyclopropanation step.