1.3- Diazepinium salts

A convenient and effective palladium-catalysed Suzuki-Miyaura cross coupling reaction of deactivated aryl chlorides with phenylboronic acid utilised the 1,3-diazepinium salts 107 as in situ precursors of the palladium ligands. These salts were prepared from the diamines 106 and cyclocondensation with triethyl orthoformate <05SL2394>. 

Triazine itself reacts with the 2,3-dihydro-l,4-diazepinium salt 75 (which acts as a nucleophile) to give the pyrinlidoI3,4- /l[l,41diazepinium salt 76 <96ZN(B)421. 

Perhaps the most consistently satisfying and enjoyable feature of the chemistry of 2,3-dihydro-1,4-diazepines and 2,3-dihydro-l,4-diazepinium salts has been their ability to provide, quite consistently, unexpected results and products. There is every hope that these compounds will continue to maintain this tradition and provide interesting new facets in their chemistry in the future. 

The lack of bromination at the 3-position is in stark contrast to the extremely ready bromination at the 6-position (analogous to the 3-position in benzodiazepines) of 2,3-dihydro-l,4-diazepines or -diazepinium salts [93AHC(56)1]. The latter compounds possess, respectively, vinamidine or vinamidinium systems, which are readily susceptible to halogenation at the central carbon atom. In contrast to these dihydrodiazepines, 1,5-benzodi-... 

Lloyd, D McNab, H., 2,3-Dihydro-1,4-diazepines and 2,3-Dihydro-l, 4-diazepinium Salts, 56, I. 

Bentazone, structure, 55, 134 Benzaldehyde, dimethylimidazolidine derivatives, lithiation, 56, 261 Benzaldehyde, p-dimethylamino-, reaction with 2,3-dihydro-1,4-diazepinium salts, 56, 30... 

Diazepinium salt, 6-bromo-2,3-dihydro-, unreactivity of bromine to nucleophiles, 56, 36... 

Diazepinium salts, 2,3-dihydro-acidity and basicity, 56, 11 N-alkylation, 56, 24 condensation with p-... 

Diazepinium salt, 2,3-dihydro-5,7-diphenyl-, electrochemical reduction, 56, 41... 

Diazepinium salts, 2,3-dihydro-6-phenyl(-2,3-di(alkyl-, aryl-), dimer formation on electrochemical reduction, 56, 43... 

Diazepinium salts, 6-halo-2,3-dihydro-nucleophilic substitution of halogen,... 

Diazepinium salts, -2,3-dihydro-, derived free radicals, 56, 32, 40... 

Diazotization, of 6-amino-2,3-dihydro-1,4-diazepinium salt, 56, 33 Dibenz[c,e][ 1,2]azaborine, 5,6-dihydro-, chlorination, bromination, 59, 309 Dibenz[i/]azepine, and 10,11-dihydro-, lithiation, 56, 273 Dibenziodole( + 1) ions, 56, 338 Dibenzo[fl,c]carbazole, 7-methoxymethyl-, lithiation, 56, 183... 

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