2008

Indole derivativesR 0140 Cinchona Alkaloid Catalyzed Enantioselective Direct Aldol-Type Reaction of

Oxinoles with Ethyl Trifluoropyruvate. — Both enantiomers (III) of trifluorometh-ylated oxindoles can be synthesized with the title method. The CF3 group is essential to achieve satisfactory enantioselectivity. Whereas substrate (Id) and its Boc analogue can be easily converted to surugatoxin building blocks [cf. (IIId)], substrate (V) gives only the racemic spirooxindole (VI) due to spontaneous cyclization caused by the ba-sicity of the benzylamino moiety. — (OGAWA, S.; SHIBATA*, N.; INAGAKI, J.; NAKAMURA, S.; TORU, T.; SHIRO, M.; Angew. Chem., Int. Ed. 46 (2007) 45, 8666-8669; Dep. Appl. Chem., Nagoya Inst. Technol., Showa, Nagoya 466, Japan; Eng.) — S. Adam

13- 121