Indoles azepinoindoles

Intramolecular oxidative palladium couplings of alkenylamino indoles allow the preparation of azepinoindole derivatives in high yields (2005MI707). 

Photocyclization of iV-chloroacetyl amines has been used previously in the synthesis of nitrogen heterocycles, and the reaction of the substituted amine (166) leads to a benzazepinone that can be elaborated to give pseudoprotopine alkaloids. Y-Chloroacetyl derivatives of the seven isomeric indolylethylamines give azepinoindoles and azocinoindoles by photocyclization. Quantum yields for the reaction are correlated with calculated (CNDO/2 and INDO) electron densities, and on this basis mechanisms are suggested the conclusion is that both indole radical cations and indolyl radicals (for the 1-substituted compounds) are... 

Bennasar also recently extended their interest in the cyclization of A -alkenyl substituted 2-indolylacyl radicals towards the annulation of larger rings [126]. A 7-endo-mg closure was observed when brotnovinyl substituted seleno ester 237 was treated with excess tin hydride in EtaB. In addition to the desired azepino[3,2-I>] indole 238, the 6-exo cyclization product 239 was observed as the minor product, with both products showing no evidence of the bromine atom in their strucmres. Previous attempts at this cyclization using a tethered allyl moiety, rather than the 2-bromo-2-propenyl tether, also gave the azepinoindole but only as the minor product. 

An example of a rhodium(I)-catalyzed cycloisomerization of nitrogen-tethered indole-alkylidenecyclopropanes 13 was reported allowing for ready access to azepinoindole derivatives 14, which are tetrahydro-P-carboline homologs (13CEJ13668). 

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