ChemInform Abstract: A Formylation-Cyclization Method of Synthesis of Cycloalkenones from Unsaturated Ketones. Part 3. Simple Synthesis of Some Functionalized Angularly Fused Cyclopentenone and Cyclopentanone Derivatives.

ChemInform Abstract

Cyclization of the ketones (I) yields the title cyclopentenone derivatives (II) which are selectively hydrogenated to afford the cyclopentanone derivatives (III). Cyclization of (Ia) and (Ib) in the presence of the orthoformate (IV) leads to the products (V), while (Ic) is only transformed to (IIc). On treatment with HClO₄ the ketones (VI) behave differently.