説明
<jats:title>Abstract</jats:title><jats:p>The past decade of organic chemistry may be charcterized as a period of violent development of new synthetic methods. This was accompained by a systematization of the analysis of synthetic problems (synthetic strategy). The planning of the synthesis of an organic target molecule is greatly facilitated by distinguishing between reagents X(C)<jats:sub><jats:italic>n</jats:italic></jats:sub>… with normal reactivity (acceptor properties at C<jats:sup>1,3,5…</jats:sup>, donor properties at X, C<jats:sup>2,4…</jats:sup>) and with reactivity umpolung (acceptor properties at X, C<jats:sup>2,4…</jats:sup>, donor properties at C<jats:sup>1,3,5…</jats:sup>). In this context, reactivity umpolung turned out to be useful as a heuristic principle, as a classification scheme, and as an aid for locating so‐called strategic bonds (synthon, transform, and antithesis according to<jats:italic>E. J. Corey</jats:italic>). There are six principal methods of umpolung: 1 2<jats:italic>n</jats:italic>‐oxidation, heteroatom exchange and modification, homologation and its reversal, the cyclopropane “trick”, use of acetylenes, and redox reactions; under certain circumstances none of these techniques is necessary in cases where direct umpolung is possible. Throughout the article, normal reactivity is indicated by green print; reactivity umpolung by red print.</jats:p>
収録刊行物
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- Angewandte Chemie International Edition in English
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Angewandte Chemie International Edition in English 18 (4), 239-258, 1979-04
Wiley