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. Author manuscript; available in PMC: 2015 Aug 11.
Published in final edited form as: Adv Synth Catal. 2014 Aug 11;356(11-12):2697–2702. doi: 10.1002/adsc.201400317

Table 1.

Optimization of reaction conditions.[a]

graphic file with name nihms604357u1.jpg
Entry Cu(OTf)2 (amount) Ligand (amount) Temp, time Yield (%)[b] ee (%)[c]
1 30 L1 (40 120 °C 84 --
mol % mol%) 24 h
2 20 L2 (25 120 °C 78 67
mol % mol %) 24 h
3[d] 20 L2 (25 120 °C 81 91
mol % mol %) 24 h
4[d] 15 L2 (19 110 °C 76 95
mol % mol %) 12 h
5[d,e] 10 L2 (13 110 °C 72 66
mol % mol %) 12 h
[a]

Conditions: Cu(OTf)2 was combined with L1 or L2 under argon and heated in dry PhCF3 (0.8 mL) for 2 h in a sealed tube. Substrate 1b (50.0 mg, 0.158 mmol), K2CO3 (0.158 mmol), MnO2 (0.473 mmol) and PhCF3 (0.8 mL) were added and the mixture was heated and stirred.

[b]

Isolated yield following flash chromatography on silica gel.

[c]

Enantiomeric excess determined by chiral HPLC analysis.

[d]

Activated flame-dried molecular sieves (20 mg/mL) were used.

[e]

Reaction did not go to completion.