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. Author manuscript; available in PMC: 2013 Jun 15.
Published in final edited form as: J Org Chem. 2012 Jun 4;77(12):5313–5317. doi: 10.1021/jo3006733

Table 2.

Rhodium(II) Catalyzed Reaction of Silyl-protected Enoldiazoacetates with Nitnle Oxidesagraphic file with name nihms-382693-t0004.jpg

entry R1 (1) Ar (2) product yield (%)b
1 Me (1a) 2-NO2C6H4 (2g) 4g 90
2 t-Bu (1b) 2-NO2C6H4 (2g) 4h 92
3 Me (1a) 2,4-(NO2)2C6H4 (2h) 4i 81
4 t-Bu (1b) 2,4-(NO2)2C6H4 (2h) 4j 88
5 Me (1a) 2-CF3C6H4 (2i) 4k 77
6 t-Bu (1b) 2-CF3C6H4 (2i) 4l 82
a

Reaction conditions: 1 (1.2 mmol) in DCM (3.0 mL) was added over 1 h via a syringe pump at 0 °C to mixture of 4 Å molecular sieves (100 mg), Rh2(pfb)4 (2.0 mol %) and nitrile oxide 2 (1.0 mmol) in DCM (5.0 mL), and stirred for another 2 h at room temperature. The crude product was hydrolyzed in THF (4.0 mL) with aqueous saturated ammonium chloride solution (2.0 mL) at 60 °C for 1~2 h.

b

Isolated yield of 4 based on limiting reagent 2.