Photocycloaddition Reactions of 2‐(Alk‐3‐en‐1‐ynyl)cyclohex‐2‐enones |
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| Authors: | Janne Möbius Paul Margaretha |
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| Affiliation: | 1. Chemistry Department, University of Hamburg, Martin‐Luther‐King Platz 6, D‐20146 Hamburg, (phone: +49?40?42?83?84?316;2. fax: +49?40?42?83?85?592) |
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| Abstract: | The newly synthesized 2‐(alk‐3‐en‐1‐ynyl)cyclohex‐2‐enones 4 undergo photodimerization (chemo‐ and regio‐)selectively at the exocyclic C?C bond to give diastereoisomeric mixtures of 1,2‐dialkynyl‐1,2‐dimethylcyclobutanes. On irradiation of 4 in the presence of 2‐chloroacrylonitrile, cyclobutane formation occurs again (chemo‐ and regio‐)selectively at the exocyclic C?C bond to afford diastereoisomeric mixtures of 2‐alkynyl‐1‐chloro‐2‐methylcyclobutanecarbonitriles. Similarly, compounds 4 undergo photoaddition to 2,3‐dimethylbuta‐1,3‐diene exclusively at the exocyclic C?C bond to afford mixtures of [2+2] and [4+2] cycloadducts. |
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| Keywords: | Photocycloadditions Cyclohex‐2‐enones Hexa‐1,5‐dien‐3‐ynes, 2‐acyl‐ |
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