Efficient Synthesis of Hexahydrocarbazoles

Abstract

Selective reduction of the nitro group in methyl 1-(2-nitrophenyl)-4-oxo-cyclohex-2-enecarboxylates with zinc-acetic acid forms hexahydrocarbazoles. The reaction is applicable to the corresponding pyridyl analogs to generate azahexahydrocarbazoles. This provides an efficient method for the generation of tricyclic framework.

Keywords:

• Azahexahydrocarbazoles
• Diels–Alder reaction
• hexahydrocarbazoles
• zinc-acetic acid reduction

ACKNOWLEDGMENTS

The authors acknowledge Dr. Francisco Talamas and Dr. Josh Taygerly for their valuable input and the analytical department for providing the spectroscopic and physical data.

Notes

^a All are isolated yields and are not optimized. Synthesis of cyclohexenones 2a–e are described in the previous paper.^{[ 4 ]}

^a All are isolated yields and are not optimized.

^b Isolated as an HCl salt.

Current name and affiliation for Christa Parmer: Christa Tatyosian, Bio-Rad Laboratories, Hercules, California, USA.