Reaction Involving the Formation of Two Bonds

The palladium-catalyzed ring heteroannulation of allenes 278 by tosyl amide and amine-containing allyl and vinyl halides (e.g., 277) provided a facile route to a variety of azepanes (e.g., 279) (Equation 39) 2003JOC6859 in the case of iV-tosyl-(2-iodophenyl)ethylamine, benzazepines are formed. 

An approach to substituted dihydroazepines 282 has been reported based on the reaction of ylides, generated in situ from styryldiazoacetates (e.g., 280), with the imines 281 (Equation 40). In the case of 280 and the imine 281 (Ar = Ph, R = Me), the dihydroazepine 282 (Ar = Ph, R = Me) was obtained in 73% yield 20010L3741 . 

Several methods have been described for the formation of azepines from Q-fragments. 1-Substituted hexahydroazepines and 3-hydroxy-1-substituted azepines may be prepared by the ruthenium-catalyzed reaction of 6-hydroxy-1-hexylamine with alcohols or the reaction of 1,6-diols with amines 82TL229, 90JMOCLU, 93JMOC39 . Alternative cyclization systems employ NaHCOj in 

4-Dihydro-5-hydroxy-5//-benz[Z ]azepines (200) are formed in high yields by rhodium-catalyzed, kinetically controlled hydroformylation of the aminoalkenes (199) at high pressures 92AJC2l . The reactions were carried out using the substrate, rhodium acetate dimer, and triphenyl phosphine in the ratio 200 1 4 at 2760 kPa at 60 C. A small amount of 3-alkyl-isoquinoline is formed in all cases. 

The intramolecular aza-Wittig reaction has been described previously as a convenient route for the synthesis of azepines, and, in a bimolecular equivalent, the reaction of 2-formyl-6-dimethyl-aminofulvene with phenyl-substituted vinyliminophosphoranes in a one-pot reaction offers a facile synthesis of phenyl-substituted 5-azaazulene (201) 91TL6727 . 

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