Table 1.

Catalyst optimization for the intramolecular Rh(II)-catalyzed dihydroazepine formation^[a]

Entry	Rh2L4	Temp.(°C)	Time	Yield 2a(%)[b],[c]
1	Rh2(Ooct)4	140[d]	0.25 h	54 (34)
2	Rh2(OAc)4	140[d]	0.25 h	47 (48)
3	Rh2(tpa)4	140[d]	0.25 h	18 (70)
4	Rh2(OPiv)4	140[d]	0.25 h	58 (18)
5	Rh2(esp)2	140[d]	0.25 h	66 (33)
6	Rh2(Adc)4	140[d]	0.25 h	68 (17)
7	Rh2(Adc)4	60	16 h	74 (14)

^[a]Only one diastereomer of the dihydroazepine product 2a was observed by ¹H NMR in all cases.

^[b]Isolated yield.

^[c]NMR yield of imine 3 in parentheses.

^[d]Reaction was performed in a microwave apparatus.