Synthesis of Rings DEF of Solanoeclepin A.

An improved synthesis of rings DEF of solanoeclepin A has been achieved from ent-Hajos Parrish ketone. A key tricyclo[5.3.2.01,6]decene intermediate having an additional vinyl group as a precursor of a hydroxyl functionality was synthesized, in which the key steps included (i) a [2,3]-Wittig rearrangement to provide trans-hydroindene with C11(R)-configuration, (ii) the introduction of a vinyl group as a masked OH at C6, (iii) an oxymercurative aldol to synthesize the tricyclo[5.3.2.01,6]decene moiety, (iv) an oxidative C-C bond cleavage to yield an aldehyde and an unsaturated methyl ketone, and (v) a radical cyclization for the cyclobutane ring formation to provide the tricyclo[5.2.1.01,6]decene compound.