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Fluorinated β‐Diketones in Reactions with Diazocyclopropane Generated in situ
Author(s) -
Tomilov Yury V.,
Guseva Ekaterina V.,
Kostuchenko Irina V.,
Ugrak Bogdan I.,
Shulishov Evgeny V.,
Nefedov Oleg M.
Publication year - 2004
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/ejoc.200400110
Subject(s) - chemistry , trifluoromethyl , yield (engineering) , lithium iodide , in situ , decomposition , iodide , lithium (medication) , azo coupling , medicinal chemistry , isomerization , organic chemistry , catalysis , alkyl , medicine , materials science , electrode , electrolyte , metallurgy , endocrinology
Treatment of 1,1‐di‐ and 1,1,1‐trifluoroalkane‐2,4‐diones 10 − 13 with cyclopropyldiazonium intermediates 2 and 3 , generated in situ through the decomposition of N ‐cyclopropyl‐ N ‐nitrosourea 1 by treatment with moist K 2 CO 3 , did not result in the expected azo coupling of the cyclopropyldiazonium ion, but afforded the corresponding oxaspiropentanes 14 − 17 as products of the addition of diazocyclopropane ( 3 ) onto one of the carbonyl groups. In addition, the reaction proceeded selectively on the carbonyl groups adjacent to the di‐ or trifluoromethyl substituents. 1,1‐Difluoroacetone reacted analogously with diazocyclopropane ( 3 ) generated in situ, giving stable 2‐(difluoromethyl)‐2‐methyloxaspiropentane in approximately 50% yield. The resulting oxaspiropentanes 14 − 17 , on heating or in the presence of lithium iodide, rearranged selectively into cyclobutanones 20 − 23 , while in the presence of Al 2 O 3 they formed mixtures of approximately equal amounts of the corresponding cyclobutanones and the 1‐vinylcyclopropanols 24 − 27 . (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)