Unusual Rearrangements of cis-4,7-Disubstituted 4,7-Dihydro4,7-dihydroxy[2.2]paracyclophanes on Dehydration: Stereoselective Formation of Planar Chiral Cyclohexadienones

✍ Scribed by Natalia Vorontsova; Valeria Rozenberg; Evgenii Vorontsov; Dmitrii Antonov; Zoya Starikova

• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: English
• Weight: 665 KB
• Volume: 2003
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/ejoc.200390119

✦ Synopsis

Abstract

Under acid conditions, cis‐4,7‐disubstituted 4,7‐dihydro‐4,7‐dihydroxy[2.2]paracyclophanes undergo dehydration accompanied by rearrangement, affording cyclohexadienone derivatives as major products and with polysubstituted phenols being formed as minor products. The formation of either an ortho or a para semiquinoid system, as well as the configuration of the newly formed asymmetric center, depended strictly on the nature of the substituent (alkyl, allyl, or phenyl). The structures of 3,4‐dihydro‐3,7‐dimethyl[2.2]paracyclophane‐4‐one (10), 3,7‐diallyl‐3,4‐dihydro[2.2]paracyclophane‐4‐one (12), and 4,7‐dihydro‐7,8‐diphenyl[2.2]paracyclophane‐4‐one (22) were determined by X‐ray structural analysis. [2.2]Paracyclophane‐4,7‐quinone (1) was obtained in optically active form. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)