Steric promotion of cyclization reactions: Substituent effect studies in the furan intramolecular diels‐alder reaction

Seven alkyl and aryl substituted N ‐allyl‐ N ‐(methylfuran)‐sulfonamide compounds have been synthesized and their rates of cyclization and equilibrium product concentrations determined. Increased steric bulk on the sulfonamide substituent has been shown to increase both the rate of cyclization and yields of these reactions. A three‐fold increase in rate and 15% increase in yield was observed as the substituent was varied from methyl to triisopropylbenzene.