2-furan-, lithium

An intramolecular 2-alkylation was also observed in a sulfonyl free radical induced addition-cyclization <95SL763>. A key intermediate in a new synthesis of pallescensin A (a biologically active labdane diterpene) was prepared by a cationic cyclization reaction with a furan <95SYN1141>. The sonochemical Barbier reaction was extended to carboxylate salts. 2-Furanylketones 10 can be obtained by sonication of a mixture of furan, lithium carboxylate, an alkylchloride, and lithium in THF <95JOC8>. 

Cl2Li02PrSi4C3oH5g, Praseodymium, bis- Ti -13-bis(trimethylsilyl)cyclopenta-dienyl]di-p-chloro-bis(tetrahydro-furan)lithium-, 27 170 Cl2Li02ScSi4C3oHjg, Scandium, bis[Ti -13-bis(trimethylsilyl)cyclopentadienyl]di-M-chloro-bis(tetrahydrofuran)lithium-, 27 170... 

Electrophihc fluorination of the 2-alkyl-furan lithium derivative with V-fluoro-... 

OjCljLiScSuCjoHsg (Continued) hydrofuran)lithium-, 27 170 OjCljLiSigYCjoHss, Yttrium, bis[ij -l,3-bis(trimethylsilyl)cyclopenta-dienyl]di-/i-chloro-bis(tetrahydro-furan)lithium-, 27 170 OjQjLiSigYbCjoHjg, Ytterbium, bis[i -l,3-bis(trimethylsilyl)cyclo-pentadienyl]di-/i-chloro-bis(tetrahydro-furan)lithium-, 27 170 OjCIgSmCgHig, Samarium,... 

Diacetates of 1,4-butenediol derivatives are useful for double allylation to give cyclic compounds. l,4-Diacetoxy-2-butene (126) reacts with the cyclohexanone enamine 125 to give bicyclo[4.3.1]decenone (127) and vinylbicy-clo[3.2.1]octanone (128)[85,86]. The reaction of the 3-ketoglutarate 130 with cij-cyclopentene-3,5-diacetate (129) affords the furan derivative 131 [87]. The C- and 0-allylations of ambident lithium [(phenylsulfonyl)methylene]nitronate (132) with 129 give isoxazoline-2-oxide 133, which is converted into c -3-hydroxy-4-cyanocyclopentene (134)[S8]. Similarly, chiral m-3-amino-4-hyd-roxycyclopentene was prepared by the cyclization of yV-tosylcarbamate[89]. 

The unsaturated tetraoxaquaterene (accompanied by linear condensation products) was first synthesized in 18.5% yield by the acid-catalyzed condensation of furan with acetone in the absence of added lithium salts. Other ketones also condensed with furan to give analogous products in 6-12% yield.A corresponding macrocycle was also prepared in 9% yield from pyrrole and cyclohexanone. The macrocyclic ether products have also been obtained by condensation of short linear condensation products having 2, 3, or 4 furan rings with a carbonyl compound. ... 

The method described here gives higher yields of the macrocyclic tetraethers and allows the product from furan and cyclohexanone to be formed directly in 5-10% yield, whereas this product was previously obtained only by an indirect route. The added lithium perchlorate undoubtedly accelerates the reaction, since after short reaction times the product was isolated in 20% yield when the salt was present and in only 5% yield when the salt was absent. The lithium cation is presumably acting as a template which coordinates with the oxygen atoms of... 

Chastrette and Chastrette showed that the cyclocooligomerization of furan and acetone was improved by the presence of lithium salts. Liotta and co-workers reported the synthesis of 12-crown-4 by a double Williamson approach in the presence of LiC104. They mention in a footnote that A run performed as detailed but without UCIO4 gave no product . Other inferential evidence has accumulated as well. 

Pyridyne (26) has been shown to exist by trapping it with furan. It must be considered to be an intermediate in the reaction of 3-bromo-2-chloropyridine (49) with lithium amalgam because in the presence of furan a small amount (2%) of quinoline (50) is formed. ... 

Quinolynes are generated and behave analogously to pyridynes. The reaction of 3-bromo-4-chloro- and 3-bromo-2-chloro-quinoline with lithium amalgam in the presence of furan gives phenanthridine (83, 9% yield) and acridine (85, 0.1% yield), respectively, via 3,4-... 

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