intra-intermolecular criss-cross cycloadditions of substitutednonsymmetricalallenyl azines with isocyanate or isothiocyanate dipolarophiles were investigated. Substituted 1,3,10-triazatricyclo[5.2.1.04,10]dec-6-en-2-ones or -dec-6-ene-2-thiones were obtained as the main products in moderate to very good yields. The thermal stabilities of the tricyclic adducts in reactions with the competing reactive dipolarophile
In the paper we indicate the increasing importance of derivatives containing a dihydropyrrolo[1,2-b]pyrazole (DPP) core. We try to show our synthetic approach based on an improved Kulinkovich method as well as our new synthetic pathway. A complex methodology involving the preparation of substituted DPPs focuses on withasomnine and the synthesis of several structurally related compounds. The developed