Enantiospecific synthesis of [2.2]paracyclophane- 4-thiol and derivatives

• Gareth J. Rowlands and
• Richard J. Seacome

Beilstein J. Org. Chem. 2009, 5, No. 9, doi:10.3762/bjoc.5.9

• range of disubstituted derivatives [33]. The basis of the strategy is the stereospecific introduction of a sulfoxide to [2.2]paracyclophane to give readily separable diastereoisomers, thus resolving the planar chirality [34]. The sulfoxide moiety is used to direct further elaboration of the [2.2

• success of this strategy was the resolution of the planar chirality of [2.2]paracyclophane by incorporation of the tert-butylsulfinyl moiety to give the diastereoisomers (Sp,RS)-5 and (Rp,RS)-5. Standard iron-catalysed bromination of 1 gave (±)-4-bromo[2.2]paracyclophane 3 in good yield [35][36]. Halogen

• the facile resolution of the planar chirality. The assignment of configuration is based on a combination of X-ray studies [33][38], formation of all stereoisomers and analogy to our previous tolylsulfinyl chemistry [31][39]. Unlike the previously prepared 4-tolylsulfinyl[2.2]paracyclophane [31