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Die Acylierung von Acetylenen mit β, γ‐ungesättigten Säurechloriden. Eine neue Synthese von 5‐Cyclopentenonen
Author(s) -
Karpf Martin
Publication year - 1984
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19840670110
Subject(s) - chemistry , acylation , intramolecular force , medicinal chemistry , ring (chemistry) , stereochemistry , organic chemistry , catalysis
The Acylation of Acetylenes with β,γ‐Unsaturated Acid Chlorides, A New Synthesis of 5‐Substituted 2‐Cyclopentenones The acylation of acetylenes with α,α‐disubstituted, β,γ‐unsaturated acid chlorides under Friedel‐Crafts ‐type conditions leads to 5‐substituted 2‐cyclopentenones. Phenols are formed with β,γ‐unsaturated acid chlorides bearing at least one α‐H‐atom. These transformations are explained by the intramolecular cyclization of the initially formed vinyl cation, which, in the cases of α,α‐disubstituted acid chlorides, is followed by ring contraction. The reaction leading to 2‐cyclopentenones is applied to the synthesis of some spiro[4.4]nona‐ and spiro[4.5]deca‐2,6‐dienones.