Zur Synthese von β‐Alkyl‐α‐methylen‐γ‐butyrolactonen

Synthesis of β‐Alkyl‐α‐methylene‐γ‐butyrolactones The ylene 1 reacts with aldehydes to give 3‐alkylidenesuccinic acid monoethyl esters 2 , which form β‐alkylidene‐γ‐butyrolactones 3 when treated with sodium diethyldihydroaluminate. Hydrogenation of the double bond leads to the β‐alkyl‐γ‐butyrolactones 4 . The β‐alkyl‐α‐methylene‐γ‐butyrolactones 5 are obtained by Mannich reaction.