Explorations of an intramolecular route to pyrrolo[3,4-b]isoxazoles: an unexpected retro-Claisen reaction

Abstract

Department of Chemistry, Loughborough University, Loughborough, Leics., LE11 3TU, Abstract Potential precursors have been prepared for intramolecular 1,3-dipolar cycloaddition to form a pyrrolo [3,4-b]isoxazole. The cycloaddition has not to date been accomplished, however an unexpected retro-Claisen reaction is reported.

Diamine‐Promoted Deacylation of 2‐Alkyl‐1,3‐Diketones for the Facile Synthesis of Ketones

“…It was therefore apparent that the diamine moiety was essential for obtaining a high yield of 3 a . This was confirmed using γ ‐aminopropanol ( 2 l ), primary amine 2 m , [23] secondary amine 2 n , cyclic amine 2 o , [36] and tertiary amine 2 p , whose reactions proceeded significantly more slowly to give mainly the starting diketone 1 a (Table 1, entries 12–16). However, DBU was found to efficiently promote the retro‐Claisen reaction (Table 1, entry 17) [21b,c,37] .…”