Suzuki reaction of vinyl triflates from six- and seven-membered N-alkoxycarbonyl lactams with boronic acids and esters

The Pd(0)-catalyzed reaction of vinyl triflates from N-alkoxycarbonyl lacta ms with different boron compounds has been studied. The coupling reaction o f alkenylboronates and arylboronic acids with six- and seven-membered lacta m-derived N-alkoxycarbonyl vinyl triflates was feasible under very mild con ditions in THF-water employing (Ph3P)(2)PdCl2 as a catalyst and Na2CO3 as a base, which provided in high yields the corresponding 6- or 7-substituted N-alkoxycarbonyl-3,4-dihydro-2H-pyridines and N-alkoxycarbonyl-2,3,4,5-tetr ahydroazepines. Allylboronates reacted slower but, with vinyl triflates fro m delta -valerolactam, still gave acceptable yields of the coupling product . Alkylboronic acids required different reaction conditions, in particular the presence of Ag2O together with a base in anhydrous toluene and (dppf)Pd Cl2 as a catalyst, affording the corresponding 6-alkyl-N-alkoxycarbonyl-3,4 -dihydro-2H-pyridines in high yields.