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. Author manuscript; available in PMC: 2016 Feb 25.
Published in final edited form as: J Am Chem Soc. 2015 Feb 16;137(7):2452–2455. doi: 10.1021/ja512746q

Table 1.

Optimization of the asymmetric α-amino radical additiona

graphic file with name nihms716466u2.jpg
entry acceptor ligand [Ru] mol% additive yield (%)b ee (%)c
1d,e 2a none 2% none 28 --
2d 2a tBuPybox (4a) 2% none 18 49
3d 2a BnPybox (4b) 2% none 75 27
4d 2a iBuPybox (4c) 2% none 15 42
5d 2a sBuPybox (4d) 2% none 70 43
6 2a sBuPybox (4d) 2% none 94 50
7 2a sBuPybox (4d) 5% none 93 59
8 2a sBuPybox (4d) 15% none 97 66
9 2a sBuPybox (4d) 2% KCl 74 59
10 2a sBuPybox (4d) 2% Bu4N+Cl− 91 67
11 2a sBuPybox (4d) 2% Bu4N+PF6− 52 43
12 2a sBuPybox (4d) 2% Bu4N+ClO4− 40 46
13 2b sBuPybox (4d) 2% Bu4N+Cl− 80 89
14 2b iBuPybox (4c) 2% Bu4N+Cl− 83 93
15f 2b iBuPybox (4c) 2% Bu4N+Cl− <5 --
16e 2b none 2% Bu4N+Cl− 52 --
17 2b iBuPybox (4c) 0% Bu4N+Cl− 0 --
18 2b iBuPybox (4c) 2% none 91 86
a

Unless otherwise noted, reactions were conducted at 0.05 M in 1 and irradiated at a distance of 30 cm from a 23 W compact fluorescent light bulb.

b

Yields determined by 1H NMR using an internal standard.

c

Enantiomeric excess determined by chiral SFC analysis.

d

Reaction conducted at 0.25 M in 1.

e

Reaction conducted without Lewis acid.

f

Reaction conducted with N,N-dimethyl amine in place of silyl amine 1.