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From 3,4‐Dinitrothiophene to Nitrocyclopropanes and 1,1′‐Dinitro‐1,1′‐bi(cyclopropyl) Compounds
Author(s) -
Armaroli Tiziana,
Dell'Erba Carlo,
Gabellini Antonella,
Gasparrini Francesco,
Mugnoli Angelo,
Novi Marino,
Petrillo Giovanni,
Tavani Cinzia
Publication year - 2002
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/1099-0690(200204)2002:7<1284::aid-ejoc1284>3.0.co;2-x
Subject(s) - cyclopropanation , diazomethane , chemistry , diastereomer , moiety , double bond , stereoselectivity , aryl , stereochemistry , medicinal chemistry , methylenecyclopropane , organic chemistry , ring (chemistry) , catalysis , alkyl
Treatment of ( E , E )‐1,4‐diaryl‐2,3‐dinitro‐1,3‐butadienes 1a − f with diazomethane in Et 2 O or THF represents a facile and high‐yielding route to 2,2′‐diaryl‐1,1′‐dinitro‐1,1′‐bi(cyclopropyl)s 2 . The process exclusively produces diastereomeric mixtures of a chiral d,l pair and a meso form, the relative percentages of which depend on the aryl moiety, consistently with a concerted syn ‐stereoselective cyclopropanation of each double bond. With 1 mol‐equiv. of CH 2 N 2 , the cyclopropanation can effectively be limited to one double bond of the starting dinitrobutadiene, thus allowing a synthetically useful differentiation between the two originally conjugated nitrovinyl moieties. As verified with model derivatives, the resulting vinylcyclopropanes 3 can be cyclopropanated with excess diazomethane to give the same diastereomeric mixtures as obtained by direct bis(cyclopropanation) of 1 . (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)