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. Author manuscript; available in PMC: 2010 Nov 4.
Published in final edited form as: J Am Chem Soc. 2009 Nov 4;131(43):15909–15917. doi: 10.1021/ja906801g

Table 3.

Optimization of the Radical-Based Conversion of Hydrazones 12 to [2.2.2] Bicyclo Systems 6a

graphic file with name nihms152570u3.jpg
Entry R (compound) Reductant (equiv) Solvent Temp. (°C) Yield (%)
1 MOM (12a) NaBH3CN (3.8)b THF 80 0c
2 PMB (12b) NaBH3CN (3.8)b THF 80 0c
3 Piv (12c) NaBH3CN (3.8)b THF 80 0c
4 SEM (12d) NaBH4 (1.4) TiHF 90 0c
5 SEM (12d) NaBH(OAc)3 (4.0) DCE:AcOH (9:1) 100 0d
6 SEM (12d) NaBH4 (8.0) CH2Cl2:MeOH (1:1) 45 50
7 SEM (12d) NaBH4 (8.0) THF:MeOH (1:1) 70 47
8 SEM (12d) NaBH4 (8.0) CH2Cl2:MeOH (1:1) 25 0c
9 SEM (12d) NaBH4 (8.0) CH2Cl2:MeOH (20:1) 45 55
10 SEM (12d) NaBH4 (8.0) CH2Cl2:EtOH (20:1) 45 60
11 SEM (12d) NaBH4 (2.0 × 3) CH2Cl2:MeOH (20:1) 45 70
12 H (12) NaBH4 (2.0 × 4) CH2Cl2:MeOH (20:1) 45 74 (6f)
a

Reactions were carried out on 0.1–1.0 mmol scale.

b

With 3.8 equiv. ZnCl2.

c

Only decomposition observed.

d

No reaction observed.