Wittig reaction basic principles

Natural product o-methylhalfordinol 117 is a basic principle of the oxa-zole alkaloids of Halfordia scleroxyla and Aegle marmelos. Annuloline 119, a blue fluorescent pigment, has been isolated from the roots of rye stalk Lolium multifiorum. The total synthesis of 2,5-disubstituted oxazole alkaloids o-methylhalfordinol and annuloline is based on the aza-Wittig reaction (Scheme 48). Thus 4-methoxyphenacylazide 115, triphenylphos-... [Pg.188]

Its principle use in organic synthesis has been as a substitute for methylene triphenylphosphorane, Ph3P= CH2, in cases where the classical Wittig reaction is too basic and causes side reactions. It is also used for the... [Pg.274]

Abstract A problem-solving approach to retrosynthesis is introduced. Basic principles for good disconnections are postulated. Examples of interconversion and disconnection of carbinols, alkenes, ketones and nitro compounds are discussed. Concepts of retro-Diels-Alder and re/ro-Wittig disconnections are presented and the mechanisms of reactions explained. Application of the Wittig reaction on the industrial scale is exemphfied by the synthesis of the analog of bombykol, the principal of pear odor and anti-appelizer chlorphentermine. [Pg.21]

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