Pergamon Tetrahedron 54 (1998) 997-1004 TETRAHEDRON Synthesis and X-Ray Crystallographic Study of 6,12- Epiiminodibenzo[b,]][1,5]diazocines Pedro Molina,* Antonio Arques, Alberto T~trraga, Maria del Rosario Ob6n Departamentode Qufmica Org~ica, Facuitadde Qufmica,Universidadde Murcia, Campusde Espinardo, E-30071Murcia,Spain Concepci6n Foces-Foces* Departamentode Cristalograffa,Institutode Qufmica-Ffsica 'Rocasolano', CSIC,Serrano 119,E-28006Madrid, Spain Nadine Jagerovic and Jos~ Elguero Instituto de Qufmica M&lica,CSIC,Juan de la Cierva3, E-28006Madrid, Spain Received 13 October 1997; revised 10 November 1997; accepted 13 November 1997 Abstract:Seven 6,12-epiiminodibenzo[bJ][1,51diazocines 2 with different substituents at position 13 have been prepared from o-(triphenylphosphoranylideneamino)benzaldehyde I and the corresponding alipha- tic and aromatic primary amines in yields ranging from 40 to 80%. The molecular and crystal structures of componds 2d (R = 4 H3C-C6H 4) and 2e (R = 4 H3CO-C6H4) have been determined by X-Ray analy- sis. Compound 2d crystallizes as a racemate while compound 2e crystallizes as a unique enantiomer (absolute configuration R,R). © 1997ElsevierScienceLtd. All rightsreserved. Although iminophosphorane 1, available by Staudinger reaction between o-azidobenzaldehyde and trip- henylphosphine, t contains the two reactive groups for an aza Wittig reaction, it has been reported that 1 itself undergoes neither intra- nor intermolecular aza Wittig reactions. 2 This lack of reactivity has been attributed to the formation of a resonance-stabilized chelate-ring involving the iminophosphorane and formyl groups. We have found that iminophosphorane 1 reacts with primary amines (benzylamine, picolylamine, ferro- H t a, R = C6Hs-CH 2 (46%) ~ C H O R.NH 2 ~ N . ~ b, R=Fc-CH2(42%) c, R = 3-CsH4N-CH2 (28%) d, R = 4 H3C-C6I-I 4 (50%) v "N=PPh3 e, R = 4 H3CO-C6H 4 (40%) ! H f, R = 4 CI-C61-14 (80%) 1 2 g, R = 4 Br-C6I-I4(52%) Scheme 1 cenylmethylamine 3 and anilines) in ethanol at room temperature in the presence of catalytic amounts of acetic acid to give the tricyclic compounds 2 containing the dibenzo[bJ][1,5]diazocine ring system in yields ranging from 40 to 80% (Scheme 1). The main interest of these compounds lies in their close analogy with Tr6ger's bases .4-7 0040-4020/98/$19.00 © 1997 Elsevier ScienceLtd. All fights reserved. PII: S01M0-4020(97) 10353-2