Initial optimization studies using 1a and MgI 2 showed that coordinating solvents were most effective (Table 1, entries 1−6), affording the azadiene 3a as the major product in low to modest selectivities and in moderate combined yield. In particular, DME was ideal for this transformation, affording the ring-expanded products after relatively short reaction times in an excellent yield, albeit with modest selectivities (entries 6 and 7). We next focused on modifying the selectivity of the ...
