Carbastannatranes: a powerful coupling mediators in Stille coupling

Stille coupling is an emerging application of carbastannatranes in organic synthesis because of their excellent tendency to transfer the axial Sn-bound hydrocarbyl substituent. Carbastannatranes have become powerful and versatile cross-coupling mediators in conventionally difficult synthetic routes for producing numerous organic compounds. These reagents belong to the most interesting class of tricyclic compounds, i.e. atranes, which captured the attention of researchers due to the uniqueness of the transannular N→M bond (bonding and variation with axial substituent). Simplicity in synthetic strategies and relatively high stability of carbastannatranes over their analogs (such as organostannanes) is responsible for a wide diversity in conveniently accessible exocyclic substituents. The particular ease of cleaving the axial Sn–C bond (due to the stability of the fused tricyclic skeleton and Sn–C bond activation by the trans-disposed N→Sn bond) made it possible to use carbastannatranes as a reagent in organic and inorganic synthesis. Due to important applications of carbastannatranes in organic synthesis, it is of utmost importance to know these reagents. Thus, a complete coverage of the reports on utilization of carbastannatranes in Stille coupling with various aspects is reported herein to facilitate and motivate the researchers working in this area.