Furan, 2-bromo-, synthesis

Furan, 2,5-bis(trimethylsilyloxy)-cycloaddition reactions, 4, 625 Diels-Alder reactions, 4, 77 synthesis, 1, 417 Furan, bromo-dipole moments, 4, 553 Furan, 2-bromo-electron diffraction, 4, 537 reactions, 4, 78 synthesis, 4, 604 Furan, 3-bromo-electron diffraction, 4, 537 Furan, 2-bromomethyl-5-nitro-reactions... 

Benzo[b]furan, 2-aryl-2,3-dihydro- H NMR, 4, 570 Benzo[b]furan, 2-bromo-nitration, 4, 604 Benzo[b]furan, 5-cinnamoyl-properties, 4, 708 Benzo[b]furan, 2-cyano-photochemical reactions, 4, 636 Benzo[b]furan, 2,3-dialkyl-synthesis, 4, 710 Benzo[b]furan, 2,3-dihydro-aromaticity... 

Furan-2-carbaldehyde, 3-amino-Friedlander synthesis, 4, 648 Furan-2-carbaldehyde, 3-azido-reduction, 4, 647 Furan-2-carbaldehyde, 4-bromo-X-ray diffraction, 4, 543 Furan-2-carbaldehyde, 5-bromo-nucleophilic substitution, 4, 612 reactions... 

Furan-2-carbonyl chloride, 5-alkyl-3,4-dichloro-synthesis, 4, 690 Furancarboxamides rotational isomerism, 4, 543 Furan-2-carboxylic acid, 5-acetylamino-ethyl ester reactions, 4, 647 Furan-2-carboxylic acid, amino-properties, 4, 708 Furan-2-carboxylic acid, 5-bromo-nitration, 4, 603, 711 Furan-2-carboxylic acid, 3-methyl-methyl ester bromination, 4, 604 Furan-2-carboxylic acid, 5-methyl-nitration, 4, 602... 

The oxidation of 2,5-disubstuted furans by singlet oxygen was exploited for the synthesis of [5,5,5] and [6,5,6] bis-spiroketals <06OL1945>. An unusual regioselective photooxidation of 3-bromofuran to 2- and 3-bromo- hydroxybutenolides, as depicted below, was reported. The mechanism for the observed base-dependent regioselective deprotonation of the endoperoxide intermediate was not determined <06OL4831>. 

There are cases known in which the use of different precursors of 221 was not equally successful in the synthesis of a certain cydoadduct. Thus, when the bromo-fluorocyclopropane 239 and 1,3-cyclopentadiene were employed as source and trapping reagent for 221, respectively, the diene was deprotonated to a large extent [66, 139], whereas this process did not play a major part on utilization of the dibromocy-clopropane 254 (Scheme 6.55). Further, an experiment to prepare the furan adducts 231-233 (Scheme 6.53) from 239 failed [66], probably because of the metalation of furan by MeLi or the carbenoid resulting from 239. 

Yasuhara et al. reported a total synthesis of furostifoline (224) by the oxidative photocyclization of 3-(indol-2-yl)-2-(isopropenyl)furan (1146), which was obtained by Sonogashira coupling of ethyl 2-ethynylphenylcarbamate (1143) with 3-bromo-2-propenylfuran (1142) (693). 

In order to testify to the versatility of the Reformatsky reaction, two examples of three-component processes are presented the synthesis of 3-aryl-4,4-dimethyl-2-oxaspiro[5.5] undecane-1,5-diones 1485 (equation 12), and the coupling of two molecules of methyl 2-bromo-2-methyl propanoate (If) with an oxoaryl acetaldehyde 15 to afford 3a-aryl-3,3,6,6-tetramethyl-tetrahydrofuro[3,2-b]furan-2,5-dione 1686 (equation 13). 

A template synthesis using Group I metal ions has recently been developed (114) for producing crown ether compounds from substituted benzenes, furans, and thiophenes, e.g., the reactions of l,2-bis(bromo-ethyl)benzene with disodium or dipotassium glycolates produced... 

The palladium-catalyzed Suzuki-Miyaura reaction of 3,5-dibromo-2-pyronc 100 with benzo[, ]furan-2-boronic acid 101 was applied to the synthesis of 3-(benzo[ ]furan-2-yl)-5-bromo-pyrone 102 in 50% yield (Equation 92) <2004SL2197>. 

Furanes. The reagent is alkylated by ai a-bromo ketone on oxygen to give an oxophosphorane, which is converted regioselci lively to a furanc. An example is the synthesis of menthofurane (2). 

Ethers can be obtained most easily by alkylating the enols as noted above, from cycloadditions to alkoxyisoxazoles (Section II,H, Part I), and from 2,2-84 or 2,5-dimethoxydihydrofurans, the latter being easily accessible by the methoxylation of furans (Sections VI,A,1 and VI,B,1, Part I) a method that has been neatly adapted to a synthesis of 3-bromo-2-methoxyfuran.8 ... 

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