147729-86-0Relevant articles and documents
Base-induced trifluoroethanolysis of acyclic di- and trihalogeno ketones: Favorskii rearrangement and [4+3] cycloaddition
Foehlisch, Baldur,Franz, Thilo,Kreiselmeier, Guenter
, p. 4687 - 4698 (2005)
Reactions of five acyclic dihalogeno- and trihalogeno ketones, representing the αα-, α,α′-, α,α,α- and α,α,α′-di- and trihalogeno substitution pattern, with sodium 2,2,2-trifluoroethoxide in 2,2,2-trifluoroethanol (NaTFE/TFE) in the presence of furan were investigated with the aim of obtaining [4+3] cycloadducts of the corresponding oxyallyl intermediates. Preference of Favorskii rearrangement over cycloaddition was observed with dichloromethyl isobutyl ketone (1a) and 1,3-dibromobutan-2-one (12) that formed mainly the trifluoroethyl esters of 3-chloro-2-isopropylpropanoic acid (9a), and (Z)-but-2-enoic acid (isocrotonic acid) (13), respectively. 9a was dehydrohalogenated to form trifluoroethyl 3-isopropylacrylate (11a). [4+3] Cycloaddition was favored with the 1,1,3-trihalogenobutan-2-ones 24 and 25, leading to 2,4-dihalogenated 8-oxabicyclo[3.2.1]oct-6-en-3-ones (26, 27) as a mixture of endo-exo-stereoisomers. With trichloromethyl isobutyl ketone (30) the isomeric 2,4-dichloro-substituted oxabicycles (34) were formed in lithium perchlorate/diethyl ether/furan/triethylamine, while in NaTFE/TFE solvolytic displacement of one chloro substituent occurred, providing 2-chloro-4- trifluoroethoxy-4-isopropyl-8-oxabicyclo[3.2.1]oct-6-en-3-one (36). By analogy, 27 reacted with sodium methoxide/methanol to form the methoxy-substituted oxabicycles 39a and 39b. Wiley-VCH Verlag GmbH & Co. KGaA, 2005.
Novel Rearrangement of 2α-Isopropyl-8-oxabicyclooct-6-ene Producing the Monoterpene 3-Hydroxyphellandral
Barbosa, Luiz Claudio de Almeido,Demuner, Antonio J.,Mann, John,Veloso, Dorila P.
, p. 585 - 588 (2007/10/02)
We describe a five-step synthesis of 2α-isopropyl-8-oxabicyclooct-6-ene from 1,1,3,3-tetrabromo-4-methylpentan-2-one, and its unexpected rearrangement to yield trans-3-hydroxy-4-isopropylcyclohex-1-enecarbaldehyde (3-hydroxyphellandral).
NATURAL PRODUCT SYNTHESIS VIA THE POLYBROMO KETONE-IRON CARBONYL REACTION
Noyori, R.,Hayakawa, Y.
, p. 5879 - 5886 (2007/10/02)
Application of the polybromo ketone-iron carbonyl reaction to natural product synthesis is summarized.The general synthesis of tropane alkaloids has been achieved via the reductive cyclocoupling of sym-tetrabromoacetone with N-methoxycarbonylpyrrole as the key step.Ready availability of 8-oxabicyclooct-6-en-3-one from the tetrabromoacetone and furan has opened a new, efficient entry to natural C-nucleosides including pseudouridine, pseudocytidine, and showdomycin.The artificial analogues such as 2-thiopseudouridine, 6-azapseudouridine, pseudoisocytidine, etc., are also obtainable.The oxabicyclic ketones bearing an isopropyl substituent at the appropriate position serve as intermediates for the synthesis of naturally occurring troponoids, nezukone, α-thujaplicin, and hinokitiol (β-thujaplicin).Carbocamphenilone and camphenic acid have been prepared through the reaction of 1,1,3-tribromo-3-methylbutan-2-one and cyclopentadiene.The cyclocondensation of α,α'-dibromo ketone and a styrene derivative leads to the single-step synthesis of α-cuparenone. 1,3-Dibromo-3,7-dimethyloct-6-en-2-one derived from nerol (or geraniol) undergoes the biogenetic-type double cyclization.The iron carbonyl-assisted intramolecular cyclocoupling gives camphor accompanied by other monoterpenic ketones.A mixture of campherenone and epicampherenone has been obtained from related dibromo ketone prepared from farnesols.The hetero reaction by use of dibromo ketones and N,N-dimethylcarboxamides, forming 3 (2H)-furanones, is employable for the preparation of muscarine alkaloid derivatives.
