Malonic Acid Derivative

The present reagent 1 is a malonic acid derivative containing a carbonyl group and employed in the synthesis of a cyclic compound as a bifunctional building block. C. Mercier, et al . have reported the usefulness of 1 in the synthesis of a cyclic enone 2 via condensation between the cyclic ketal of 1 and α-chlorocyclopentanone in the presence of a base, followed by hydrolysis and ring-closing reaction. E. E. Schweizer, et al . also have reported usefulness of 1 by synthesis of cyclopentene 3 from the reaction of 1 with a vinyl phosphonium salt.