Rh(I)-catalyzed hydroacylation/cycloisomerization cascade: synthesis of (±)-epiglobulol

A novel Rh(I)-catalyzed cascade reaction was developed by combination of a hydroacylation of 4,6-dienal and a cycloisomerization of the resultant triene, giving the bicyclo[5.3.0]decenone derivative 8b in a stereoselective manner. It was found that the Thorpe-Ingold effect played an important role in the second cycloisomerization step of this cascade cyclization. From the cascade cyclization product, (±)-epiglobulol could be synthesized.