Functionalized Cyclic Disilenes via Ring Expansion of Cyclotrisilenes with Isocyanides

The reaction of cyclotrisilenes <b>1</b> with 1 equiv of alkyl and aryl isocyanides at 25 °C affords the four-membered trisilacyclobutenes <b>2</b> with an exocyclic imine functionality as the major products of formal insertion into one of the Si–Si single bonds of <b>1</b>. Minor quantities of the iminotrisilabicyclo[1.1.0]­butanes <b>3</b> are obtained as side products, formally resulting from [1 + 2] cycloaddition of the isocyanides to the Si–Si double bond of <b>1</b>. The bicyclo[1.1.0]­butanes <b>3</b> become dominant at lower temperatures and may react with an additional 1 equiv of isonitriles to give the diiminotrisilabicyclo[1.1.1]­pentanes <b>4</b>

Functionalized Cyclic Disilenes via Ring Expansion of Cyclotrisilenes with Isocyanides

The reaction of cyclotrisilenes <b>1</b> with 1 equiv of alkyl and aryl isocyanides at 25 °C affords the four-membered trisilacyclobutenes <b>2</b> with an exocyclic imine functionality as the major products of formal insertion into one of the Si–Si single bonds of <b>1</b>. Minor quantities of the iminotrisilabicyclo[1.1.0]­butanes <b>3</b> are obtained as side products, formally resulting from [1 + 2] cycloaddition of the isocyanides to the Si–Si double bond of <b>1</b>. The bicyclo[1.1.0]­butanes <b>3</b> become dominant at lower temperatures and may react with an additional 1 equiv of isonitriles to give the diiminotrisilabicyclo[1.1.1]­pentanes <b>4</b>