Photoactive Phanes, II. – X-ray Structure and Photoreactivity ofpseudo-gem Cinnamophane Dicarboxylic Acid {bis-4,15-(2′-Hydroxycarbonylvinyl)[2.2]paracyclophane}
✍ Scribed by Meyer, Ulrich ;Lahrahar, Nacer ;Marsau, Pierre ;Hopf, Henning ;Greiving, Helmut ;Desvergne, Jean-Pierre ;Bouas-Laurent, Henri
- Book ID
- 102365949
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 386 KB
- Volume
- 1997
- Category
- Article
- ISSN
- 0947-3440
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✦ Synopsis
Abstract
The pseudo‐gem cinnamophane dicarboxylic acid 1 was shown to undergo a stereospecific [2 + 2] photocycloaddition in the solid state, generating the truxinic acid derivative 2 in 100% chemical yield; the reaction can proceed to completion because it is not an “independent site” solid state reaction. The X‐ray structure of 1 reveals that its molecules are associated in dimers formed from four almost linear hydrogen bonds. A salient feature is the intramolecular centre‐to‐centre distance between the reacting double bonds of ≈3.37 Å, the smallest known to date. In contrast to trans‐cinnamic acid, the topochemical [2 + 2] photocycloaddition occurs also in solution, with a quantitative chemical yield and a quantum yield of ≈0.55 (in methanol).