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Synthesen von (1 R )‐ cis ‐3‐(2′,2′‐Dihalovinyl)‐2, 2‐dimethylcyclopropan‐carbonsäuren via Favorskii ‐Umlagerung von optisch aktiven Cyclobutanonen
Author(s) -
Greuter Hans,
Dingwall John,
Martin Pierre,
Belluš Daniel
Publication year - 1981
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.19810640843
Subject(s) - chemistry , racemization , optically active , amine gas treating , medicinal chemistry , adduct , stereochemistry , organic chemistry
Syntheses of (1 R )‐ cis ‐3‐(2′,2′‐Dihalovinyl)‐2,2‐dimethylcyclopropane Carboxylic Acids via Favorskii ‐rearrangement of Optically Active Cyclobutanones The cis ‐cyclobutanones 7 are resolved by means of optically active amine salts of their sodium hydrogen sulfite adducts. The desired (1 R )‐ cis ‐carboxylic acids 9 are obtained from the (+)‐ cis ‐cyclobutanones 7 via Favorskii ‐rearrangement and HX‐elimination. The recycling of undesired (−)‐ cis ‐cyclobutanones 7 is carried out in good yield by their racemization, thus rendering the total synthesis 1 + 2 → 9 chirally economic.