Stereoselective Synthesis of -Decalin-Based Spirocarbocycles via Photocyclization of 1,2-Diketones.

Diastereoselective synthesis of the -decalin-based α-hydroxyl butanone spirocarbocycles bearing all-carbon quaternary stereogenic centers has been achieved via Norrish-Yang photocyclization of -decalin-substituted-2,3-butanediones using daylight. Density functional theory (DFT) calculations suggest that this diastereoselective reaction is affected by both substrate conformation and intramolecular hydrogen bonds. The developed chemistry could be applied to synthesizing the derivatives of the -decalin-based biologically important natural products.