Conversion of O‐Propargyl β‐enones to 2‐Allylidene 1,3‐Diones and Furan Derivatives via [3,3]‐Sigmatropic Rearrangement.

An efficient synthetic protocol was developed for the formation of 2‐allylidene 1,3‐diones in very good yields via [3,3]‐sigmatropic rearrangement of O‐propargyl β‐enones. Good yields of highly functionalized substituted furan derivatives were synthesized from O‐propargyl β‐enones under gold‐catalysis via intramolecular cycloisomerisation. We have developed an efficient method for synthesis of several new 2‐allylidene 1,3‐diones in very good yields under thermal condition via [3,3]‐sigmatropic rearrangement. Further, O‐propargyl β‐enones were directly converted to the corresponding substituted furan derivatives under gold‐catalysis via cyclo‐isomerisation. Moderate to good yields of substituted furan derivatives were generated with significant molecule complexity in one‐pot. [ABSTRACT FROM AUTHOR]