Ethylene, 1 -nitro-2- reaction with azomethine ylides

The same chiral auxiliary has been used in the cycloaddition of an optically active azomethine ylide to benzaldehyde and to l-nitro-2-(3,4-methylenedioxyphenyl)ethylene Ae ylide was generated in situ by treating (R)-(+)-/V-(l-phenylethyl)-A -cyanomethyl-A -trimethylsilylmethylamine (33) with silver fluoride. Unfortunately, no selectivity was observed in the first case and only a 3 2 preference was expressed in the second. Use of the azomethine ylide derived in the same manner from (/ )-(-)-N-(l-phenyl-2-methoxyethyl)-/V-cyanomethyl-N-trimethylsilylmethylamine (34) displayed a modest, but potentially useful, 4 1 diastereofacial selectivity in its reaction with l-nitro-2-(3,4-methylenedioxyphenyl)ethylene. The precise structure of the major and minor product was not determined (Scheme 25). 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ , ]

See also in sourсe #XX -- [ ]

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