Synthesis of 1-(2-Aminovinyl)indoles and 1,3′-Biindoles by Reaction of 2,2-Diaryl-Substituted 2H-Azirines with α-Imino Rh(II) Carbenoids

• DOI: 10.1021/acs.joc.8b03205
• Publication Date: 2019-01-27T16:07:03Z
• Authors: Adel R. Khaidarov; Nikolai V. Rostov...; Andrey A. Zolotarev; Alexander F. Khle...; Mikhail S. Novikov
• Keywords: 01 natural sciences; 0104 chemical sciences

An effective and operationally simple method for the preparation of 1-(2-(sulfonamido)vinyl)indoles (SAV-indoles) by Rh(II)-catalyzed reaction 2,2-diaryl-2H-azirines with 1-sulfonyl-1,2,3-triazoles has been developed. This enables stereoselective synthesis a variety 1,2,3-trisubstituted indoles having Z configuration (1-aryl-2-(sulfonamido)vinyl) substituent. The mechanism, supported DFT calculations, involves formation 1,4-diazahexa-1,3,5-trienes, which rapidly cyclize to 2,2-diaryl-1-sulfonyl-1,2-dihydropyrazines. These compounds can be isolated at an early stage reaction, but under prolonged heating they isomerize into 7aH-indolium ylides, followed barrierless 1,5-prototropic shift SAV-indoles. developed methodology was also applied 1,3′-biindoles from using 3-diazoindolin-2-imines instead 1-sulfonyl-1,2,3-triazoles.