Synthesis of polycyclic aminocyclobutane systems by the rearrangement of N-(ortho-vinylphenyl) 2-azabicyclo[3.1.0]hexane derivatives.

The acid-catalysed thermal rearrangements of a family of N-aryl 2-azabicyclo[3.1.0]hexanes is described. These substrates, designed in such a way that the aromatic system is conjugated with an alkene group located at the ortho position relative to the nitrogen atom, have been prepared by using an intramolecular Kulinkovich-de Meijere reaction. The rearrangements can then be conducted either under standard thermal conditions or with microwave activation. Depending on the conditions applied and the substitution pattern, dihydroquinoline or polycyclic aminocyclobutane derivatives can be obtained. A mechanistic discussion is provided, with the proposition of the initial protonation of the aminocyclopropane moiety to give an iminium intermediate. By analogy with related intermolecular reactions, the involvement of electrocyclic reactions among the series of elementary steps that follow is put forward.

Progress towards the total synthesis of trichodermamides A and B: construction of the oxazine ring moiety.

Trichodermamides are modified heterocyclic dipeptides that possess a unique 4H-5,6-dihydro-1,2-oxazine ring. Starting from affordable, easily available (-)-quinic acid, the enantioselective synthesis of this oxazine moiety was achieved by an intramolecular epoxide ring-opening reaction by an oxime. [structure: see text]