Routes to enantiomerically pure dienyl sulfoxides

The first report concerning the synthesis of enantiomerically pure dienyl sulfoxides was made by Hoffmann and coworkers [32], who made use of the Horner-Wittig reaction between an a-phosphoryl sulfoxide and acrolein to give the corresponding dienyl sulfoxides as a mixture of geometric isomers. Recently, there has been considerable interest in the synthesis of 1-sulfinyl and 2-sulfinyl-l,3-butadienes, as these types of substrates have considerable potential as diene components in asymmetric Diels-Alder cycloadditions. 

Similar methodology has been employed by the same group in the synthesis of enantiomerically pure 4-substituted-(lZ,3 )-l-[(/ )-p-tolylsulfinyl]-2-t-butyldi-methylsilyloxy-1,3-butadienes [35]. 

Nonracemic l-methoxy-3-sulfinyl-l,3-butadienes derived from 10-mercapto-isobomeol have been prepared by the cycloaddition of (15)-isobornyl-10-sulfenic acid to (Z)- and ( )-l-methoxybut-l-en-3-yne. High levels of asymmetric induction were observed for the cycloaddition in some cases [40]. 

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