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. Author manuscript; available in PMC: 2020 Apr 5.
Published in final edited form as: Org Lett. 2019 Mar 12;21(7):2317–2321. doi: 10.1021/acs.orglett.9b00602

Table 1.

Optimization of the annulation process.a

graphic file with name nihms-1017551-t0007.jpg
entry a X photocat.b solvent time (h) yield (%)c
1 Cl [Ru] DMF 16 8
2 Br [Ru] DMF 16 20
3 I [Ru] DMF 16 10
4d Br [Ru] DMF 48 46
5 e Br [Ru] DMSO 16 46
6 e Br [Ir] DMSO 16 54
7e Br 4CzIPN DMSO 16 35
8 f Br [Ir] DMSO 16 60
9 f Br [Ir] DMSO 0.5 59
10f,g Br [Ir] DMSO 16 –
11f Br – DMSO 16 17h
a

Conditions unless otherwise noted: silicate (5 equiv, 1.5 mmol), imine (1.0 equiv, 0.3 mmol), photocatalyst (2 mol %), DMSO (0.1 M), irradiating with 21 W CFL.

b

Photocatalyst: [Ru] = [Ru(bpy)3](PF6)2 and [Ir] = [Ir{dF(CF3)2ppy}2(bpy)]PF6.

c

Isolated yield after purification.

d

2 equiv of silicate used.

e

A 1:2 silicate/imine ratio used along with 4 W blue LEDs.

f

A 1:2 silicate/imine ratio used along with 30 W blue LEDs.

g

Reaction conducted in the dark.

h

NMR yield of crude reaction mixture.