L tetrafluoroborate

C. 7 ricar6oni/Z[( 1,2,3,4,5-jj)-l-and 2-methoxy-2,4 -cydohexadien-l-yl]-irTriphenylmethyl tetrafluoroborate [Methylium, triphenyl-, tetrafluoroborate] (34 g., 0.103 mole) (Note 20) is dissolved in a minimum volume of dichloromethane and 18 g. (0.072 mole) of tricarbonyl (1- and 2-methoxy-l,3-cyclohexadiene)iron dissolved in a like volume of dichloromethane is added. The resulting dark solution is left for 20-30 minutes and then added with stirring to three times its volume of ether (Note 21). The precipitate is collected and washed with ether to 5ueld 21-22 g. (87-91%) of product as yellow solid (Note 19). 

Manufacture of rhodium precatalysts for asymmetric hydrogenation. Established literature methods used to make the Rh-DuPhos complexes consisted of converting (1,5-cyclooctadiene) acetylacetonato Rh(l) into the sparingly soluble bis(l,5-cyclooctadiene) Rh(l) tetrafluoroborate complex which then reacts with the diphosphine ligand to provide the precatalyst complex in solution. Addition of an anti-solvent results in precipitation of the desired product. Although this method worked well with a variety of diphosphines, yields were modest and more importantly the product form was variable. The different physical forms performed equally as well in hydrogenation reactions but had different shelf-life and air stability. 

As a consequence of the cyclobutyl to homoallyl rearrangement, reactions of 1-chloro-, 1-bro-mo-l,2-dimethylcyclobutane, 1-chloro- or l-bromo-l,3-dimethylcyclobutane with silver(I) te-trafluoroborate in diethyl ether gave in each case the same open-chain compound 2-fluoro-4-mcthylpent-4-ene (14) as the major product. Thus, l-bromo-l,3-dimethylcyclobutane (13) was treated with silver(l) tetrafluoroborate in diethyl ether at 0 >C to give 2-fluoro-4-methylpent-4-ene (14).22... 

Cycloheptatrieny1tr icarbonyl -chromium(O), AQ<86 rr-Cycl oheptatr ienyl tr icarbony I -iron(l) tetrafluoroborate, AR09 rr-Cycl oheptatr ienyl tr i carbonyl -molydenum(o), AQ88 1,2-Cyclohexadienedione, AG07 (it-Cyc 1 ohexad i ene) tr i carbony I -iron(o), A09O... 

Silver(l) tetrafluoroborate and indium(m) chloride can also promote the reaction of propynoic esters with phenols to afford coumarins. However, substitution of the alkyne is not tolerated for the silver(l) promoted reaction <2003JA4518, 2004SC1909>. 

The preparation of vinyl nitrones by catalytic cyclization of allenic oximes has been demonstrated. Oxime 75, prepared from 5,6-heptadienal, was cyclized to nitrone 76 in the presence of silver(l) tetrafluoroborate. This was trapped by, for example, styrene to give 77. Such a compound again opens up a route to 2,6-disubstituted piperidines (85TL6249). 

BICYCLO[2.2.1]HEPTA-2,5-DIENE)[1,4-BIS(DIPHENYLPHOSPHINO)BUTANE]RHODIUM(l)TETRAFLUOROBORATE... 

For a more detailed discussion, see Bis(cyclohexyl isocyanide)gold(l) Tetrafluoroborate-(R)-N-[2-(N,N-Dimethylamino)ethyl]-N-methyl-l-[(S)-l, 2-bis diphenylphosphino)ferrocenyl]ethylamine. 

Benzene-1,2-diamine derivatives 9 react with tetrakis(acetonitrile)copper(l) tetrafluoroborate via smooth cyclization and aromatization to afford quinoxaline derivatives 10. ... 

DICARBONYLCu -CYCLOPENTADIENYL) (2-methyl-i-propenyl-kC )iron and DICARBONYL(n -CYCLOPENTADIENYL)(ii. 2-METHYL. l-PROPENE)IRON(l+) TETRAFLUOROBORATE... 

TRIS[1,3-BIS(DIPHENYLPHOSPHINO)PROPANE]-HEPTAH YDRIDOTRIIRIDIUM 2 + ) BIS(TETRAFLUOROBORATE) AND BIS[1,3-BIS-(DIPHENYLPHOSPHINO)PROPANEI-PENTAH YDRIDODllRIDlUM(l + ) TETRAFLUOROBORATE ... 

Bis(pyridine)iodonium(l) tetrafluoroborate reagent for 1,2-iodofunctionaiization of isolated or conjugated olefins, or cyclization of alkynyl sulfides. 

E. j/-HYDRIDO(NITRATO-0,0 )BIS(TRIPHENYLPHOSPHINE) BIS(TRIPHENYLPHOSPHINEGOLD)IRIDIUM(l-l-) TETRAFLUOROBORATE(l -)... 

DICARBONYL(ti -CYCLOPENTADIENYL) (2-METHYL-1-PROPENYL-kC )IRON and DICARBONYL(ti -CYCLOPENTADIENYL)(ti -2-METHYL-l-PROPENE)IRON(l + ) TETRAFLUOROBORATE... 

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