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. Author manuscript; available in PMC: 2010 Jan 8.
Published in final edited form as: Angew Chem Int Ed Engl. 2009;48(34):6328–6331. doi: 10.1002/anie.200902420

Table 1.

Catalyst Optimization Studies

graphic file with name nihms162524u2.jpg
Entry Catalyst R1 R2 R3 R4 R5 ee (%)
1 3 -- -- -- -- -- −14
2 4a Me H tBu tBu tBu 55
3 4b H H tBu tBu tBu 35
4 4c Me H tBu tBu NO2 13
5 4d Me H tBu tBu OTIPS 21
6 4e Me H tBu tBu Cl 40
7 4f Me H tBu Me tBu 23
8 4g Me H tBu SiEt3 tBu 65
9 4h Me (S) Me tBu SiEt3 tBu 75
10 4i Me (R) Me tBu SiEt3 tBu 80
11 4j Me (R) Me CH2Ph SiEt3 tBu 89
12 5 93