Synthesis and Asymmetric Diels-Alder Reactions of Enantiopure 3-(Alkylsulfinyl)-1-methoxy-1,3-butadienes.
Simple syntheses of enantiopure (E)- and (Z)-3-(alkylsulfinyl)-1-methoxy-1,3-butadienes 2and 3 were provided by the addition of (1S)-isoborneol-10-sulfenic and (S)-phenyl-2-hydroxyethanesulfenic acids 8 to (E)- and (Z)-1-methoxybut-1-en-3-ynes (9) and (10). These additions proceeded with asymmetric induction, the extent of which depended upon the nature of the chiral hydroxyalkyl group. Cycloadditions of methyl acrylate to the enantiopure dienes proceeded with complete regioselectivity and very high stereoselectivity when catalyzed by lithium perchlorate or zinc chloride in dichloromethane. The chirality at sulfur controlled the diastereofacial selectivity in these Diels-Alder cycloadditions.
Aversa
Maria C.
MC
Department of Chemistry, University of Sheffield, Dainton Building, Brook Hill, Sheffield S3 7HF, U.K.
Barattucci
Anna
A
Bonaccorsi
Paola
P
Giannetto
Placido
P
Jones
David Neville
DN