Sulfolane 26 was found to be an improvement over DMSO (Entry 19); however, temperatures higher than 80 °C for 24 h led to decomposition (Entries 20-22). Decreasing the temperature to 60 °C led to a ten-fold decrease in NMR yield (Entry 18). Metal additives known to promote carbocation formation from alkyl halides, such as silver oxide and zinc oxide were tested and resulted in lower analytical yields than did additivefree conditions (Entries 23-24). We further examined the substrate scope of the BCP to BCB reaction in sulfolane (Scheme 3). Secondary amine nucleophiles commonly employed in medicinal chemistry were tolerated such as morpholine (3), piperidine ( ), and a ketalprotected piperidone (5). Imidazole delivered 6 in 35% isolated yield after 3 days of heating in sulfolane at 80 °C. 1,2,3,4tetrahydroisoquinoline afforded 7 in 41% yield after a short microwave reaction. We found that microwave heating can quickly probe whether the reaction will be successful, and in many cases isolated yields were comparable to those of conventional heating (See Table -S2). For the preparation of compound 11, microwave heating gave better performance.