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Synthesis from Non-heterocycles

RING SYNTHESIS FROM NON-HETEROCYCLIC COMPOUNDS FORMATION... [Pg.657]

Ring synthesis from non-heterocycles by closure y to the heteroatom are reported. Sulfonium ylides (135) with active methylene compounds such as malononitrile give a C-phenacyl product (136) however, when reacted with /3-diketones and /3-ketonic esters they produce furans quantitatively (74CL101). In these cases O-phenacylation takes place followed by cyclization to give the 3-hydroxydihydrofuran (137), which is dehydrated to the furan (138) (Scheme 30). These furans differ from those formed by the reaction of the diketone or ketonic esters with phenacyl halides. The latter reaction takes place by C-phenacylation, yielding the isomeric furans (139). [Pg.669]

See other pages where Synthesis from Non-heterocycles is mentioned: [Pg.90]    [Pg.168]    [Pg.274]    [Pg.131]    [Pg.166]    [Pg.67]    [Pg.69]    [Pg.395]    [Pg.396]    [Pg.95]    [Pg.115]    [Pg.90]    [Pg.95]    [Pg.115]    [Pg.90]    [Pg.131]    [Pg.166]    [Pg.177]    [Pg.216]    [Pg.463]    [Pg.898]    [Pg.931]    [Pg.67]    [Pg.69]    [Pg.395]    [Pg.396]    [Pg.168]    [Pg.457]    [Pg.457]    [Pg.791]    [Pg.825]    [Pg.168]    [Pg.274]    [Pg.457]    [Pg.457]    [Pg.791]    [Pg.825]    [Pg.95]    [Pg.115]    [Pg.79]   


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