Ugi multicomponent reaction followed by an intramolecular nucleophilic substitution: convergent multicomponent synthesis of 1-sulfonyl 1,4-diazepan-5-ones and of their benzo-fused derivatives.
A short, two-step approach to the synthesis of diazepane or diazocane systems, based on a Ugi multicomponent reaction followed by a subsequent intramolecular SN2 reaction was studied. 1-sulfonyl tetrahydrobenzo[e]-1,4-diazepin-1-ones 1 were obtained in very high yield through a Ugi multicomponent reaction followed by Mitsunobu cyclization. On the other hand, aliphatic 1-sulfonyl 1,4-diazepan-5-ones 2 could be obtained employing different cyclization conditions (sulfuryl diimidazole). A similar approach toward diazocane rings using hydroxamates as nucleophiles was less successful, affording only O-cyclized adducts or unexpected side products. A mechanistic explanation of the observed outcomes is proposed.
Banfi
Luca
L
Dipartimento di Chimica e Chimica Industriale, via Dodecaneso 31, I-16146 Genova, Italy. banfi@chimica.unige.it
Basso
Andrea
A
Guanti
Giuseppe
G
Kielland
Nicola
N
Repetto
Claudio
C
Riva
Renata
R
D001381:Azepines / Q000138:chemical synthesis*; D001552:Benzazepines / Q000138:chemical synthesis*; D003500:Cyclization; D006571:Heterocyclic Compounds / Q000138:chemical synthesis
D001381:Azepines; D001552:Benzazepines; D006571:Heterocyclic Compounds