Paracyclophanes: Extending the Bridges. Synthesis

Preparatively satisfactory routes to [3.2]paracyclophane (10), [4.2]paracyclophane (14), [4.3]paracyclophane (19) as well as several derivatives of these compounds - among others the bromides 25, the ester 31, the diesters 40-43 - are described using well-established methods of cyclophane chemistry (ring-closure reactions leading to thiacyclophanes, ring contraction by sulfone pyrolysis). The parent systems and their derivatives are now available in gram quantities allowing a study of their chemical properties. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)