γ-Cyclodextrin mediated photo-heterodimerization between cinnamic acids and coumarins

• Photo-heterodimerization, a relatively less studied reaction, has been effected.
• The reported method is simple, effective, and general.
• Computational chemistry shed light on supramolecular characteristics of H–G complex.
• Weak intermolecular interactions were strong enough to direct photochemistry.
• Selectivity of more than 50% heterodimer observed in four out of 10 alkene pairs.

The ability of γ-cyclodextrin to form ternary inclusion complexes has been utilized to mediate photo-heterodimerization between cinnamic acids and coumarins in the solid-state. Stabilizing steric and electronic interactions between the alkenes in the inclusion complex appear to be primarily responsible for directing the complexation toward the 1:1:1 hetero-guest pair complex. Photoexcitation of the complex resulted in formation of the heterodimers in proportions significantly higher than the combined yields of the homodimers for alkene pairs in which complementary electronic and/or steric characteristics were present.

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