Chiral vinyl sulfoxides intramolecular addition

The application of chiral sulfoxides to the asymmetric synthesis of biologically active compounds has recently been reviewed [3]. Conjugate addition to chiral vinyl sulfoxides has been used by several research groups to achieve the enantioselective synthesis of natural products. For example, intramolecular asymmetric conjugate addition of a nitrogen nucleophile to a chiral vinyl sulfoxide (Scheme 3) was studied by Pyne and applied to the enantioselective synthesis of (-R)-carnegine and other alkaloid systems (Scheme 3) [10]. 

The intramolecular conjugate addition of nucleophiles to chiral vinyl sulfoxides has proved particularly useful in the asymmetric synthesis of a variety of natural products. 

The intramolecular addition of amines to chiral vinylic sulfoxides has been investigated by Pyne and coworkers as an approach to various chiral natural products such as ( )-(+)-carnegine (86) [60, 61] and (+) and (-)-sedamine (87) [61]. As an outline of this methodology, Pyne s approach to the chiral isoquinoline, ( )-(+)-carnegine (86), is described below. 

The sulfinyl group is a useful temporary chiral auxiliary for the activation of a carbon carbon double bond towards nucleophilic addition as both enantiomers of a,//-unsaturated vinyl sulfoxides are available in enantiomerically pure form91. Both intermolecular and intramolecular conjugate additions of V-nucleophiles have been investigated. 

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