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Vinyl sulfoxides natural products

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]. [Pg.106]

The synthesis of the natural product (-)-sibirine (72), a compound containing an unusual 2-azaspiro[5,5]undecane skeleton, was described by Iwata [53], The method involved initial attack of allylmagnesium bromide on the non-racemic vinylic sulfoxide (73) (Scheme 4.38), followed by a Pummerer-type reaction (or isomerization) of the double bond as illustrated in Scheme 4.39 [54]. [Pg.127]

The intramolecular conjugate addition of nucleophiles to chiral vinyl sulfoxides has proved particularly useful in the asymmetric synthesis of a variety of natural products. [Pg.129]

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. [Pg.131]

Olefination of the aldehyde of 196 installed an additional carbon necessary for advancement to the natural products, giving methyl vinyl ether 197. Treatment with dimethyldioxirane at low tenperature acconplished oxidation at sulfur in the presence of the electron-rich vinyl ether, and the resulting sulfoxides (mixture of diastereomers at sulfur) underwent high-yielding Mislow-Evans rearrangement to allylic alcohol 198 under mild conditions in methanol containing trimethylphosphite and di-zso-propyl amine. The product 198 of this sequential Claisen/Mislow-Evans process was converted to either (-)-joubertinamine or (-)-mesembrine in a short series of steps. [Pg.727]


See other pages where Vinyl sulfoxides natural products is mentioned: [Pg.71]    [Pg.30]    [Pg.841]    [Pg.40]    [Pg.687]    [Pg.170]    [Pg.71]    [Pg.874]    [Pg.375]    [Pg.154]    [Pg.315]    [Pg.686]    [Pg.645]    [Pg.161]    [Pg.126]    [Pg.126]    [Pg.126]    [Pg.56]   
See also in sourсe #XX -- [ Pg.117 , Pg.129 , Pg.130 , Pg.131 , Pg.132 ]




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