Ethylene derivatives boronic

Peroxydicarbonates s. Diisopropyl peroxydicarbonate Peroxydisnlfate s. Persulfate Peroxymaldc acid 26,136 Peroxymercuration of ethylene derivs. 26, 637 Persolfate 26,137 Peroxytrifluoroacetic acid as reagent 26, 137, 529 —/boron fluoride, oxidations with -, review 19, 161 suppl. 26 pH s. Buffer solns. 

Boronic acid esters from ethylene derivatives G G GHG B(OR)2... 

Phosphoric acid-boron fluoride C-Alkylation of arenes with ethylene derivatives... 

The paper describes the first asym. hydroboration with a chiral catalyst. E A soln. of norbornene and catalytic amounts of chloro(l,5-cyclooctadiene)rhodium(I) dimer and DIOP (2,3-0-isopropylidene-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane) in THF flushed with argon, stirred at 20° for 15 min, cooled to —78°, 1.2 eqs. catecholborane added, stirred for 5 min, allowed to warm to —40°, maintained at this temp, for 72 h, recooled to —78°, ethanol, 3 M NaOH, and 30% H2O2 added, the mixture allowed to warm to 25° during ca. 1 h, then stirred for 12h cjco-(lR, 2R)-norborneol. Y 99% (e.e. 55%). The method is generally applicable (even to 1,1-disubst. ethylene derivs. ) and expensive chiral boron-reagents are not necessary. F.e.s. K. Burgess, M.J. Ohlmeyer, J. Org. Chem. 53, 5178-9 (1988) from allyl alcohol O-derivs. s. Tetrahedron Letters 30, 395-8 (1989). 

Osmium tetroxidejN-methylmorpholine N-oxide Cyclic glycol boronates from ethylene derivs. 

Di(isopinocampheyl)borane Resolution of racemic ethylene derivatives with optically active boranes s. 19, 720 Lithium tetrahydridoborate s. under (C2H )gN,HCl Sodium tetrahydridoborate/boron fluoride Boranes from ethylene derivatives s. 16, 753... 

Sodium boron hydride/boron fluoride Boranes from ethylene derivatives s. 15, 69... 

Boron fluoride/sodium tetrahydridoborate Alcohols from ethylene derivatives Asym. synthesis... 

Peroxytrifluoroacetic acid/boron fluoride Ketones from ethylene derivatives with Wagner-Meerwein rearrangement... 

Unsubstituted 20-ketones undergo exchange dioxolanation nearly with the same ease as saturated 3-ketones although preferential ketalization at C-3 can be achieved under these conditions. " 20,20-Cycloethylenedioxy derivatives are readily prepared by acid-catalyzed reaction with ethylene glycol. The presence of a 12-ketone inhibits formation of 20-ketals. Selective removal of 20-ketals in the presence of a 3-ketal is effected with boron trifluoride at room temperature. Hemithioketals and thioketals " are obtained by conventional procedures. However, the 20-thioketal does not form under mild conditions (dilution technique). ... 

In another approach to analogs, nortestosterone is first converted to the thioketal by treatment with ethylene dithiol in IUe presence of boron trifluoride. (The mild conditions of this reaction compared to those usually employed in preparing the oxygen ketals probably accounts for the double bond remaining at 4,5.) Treatment of this derivative with sodium in liquid ammonia... 

Note that ethylbenzene is a derivative of two basic organic chemicals, ethylene and benzene. A vapor-phase method with boron trifluoride, phosphoric acid, or alumina-silica as catalysts has given away to a liquid-phase reaction with aluminum chloride at 90°C and atmospheric pressure. A new Mobil-Badger zeolite catalyst at 420°C and 175-300 psi in the gas phase may be the method of choice for future plants to avoid corrosion problems. The mechanism of the reaction involves complexation of the... 

If a diastereomeric mixture of (S,S)-2,5-dimethyl-3.4-hexanediol esters 2 and 3 reacts with methylmagnesium bromide, the result is kinetic resolution, as verified for R1 = Bn. The diastereomeric mixture was prepared from the racemic ethylene glycol a-chloro boronic ester via transesterification with chiral diol. The products isolated were (S,S)-2,5-dimethyl-3,4-hexanediol [(/ )-2-phcnyl-l-methylethyl]boronate, diastereomeric ratio >95 5 as indicated by the rotation of the (/ )- -phenyl-2-propanol derived by deboronation with hydrogen peroxide, and (S,S)-2,5-dimethyl-3.4-hexanediol methylboronate. Phenylacetaldehyde was identified by 1H NMR4. 

Tetraborane and ethylene react in a 1 1 ratio to form B4Hi2C2 and hydrogen 50) the Bn and II1 spectra permit a unique structural assignment to be made for the B4 derivative 124). In the B11 spectrum, the low field triplet found in B4H40 becomes a doublet and the high field doublet is unchanged. Thus, the Ba boron atoms now have only one terminal hydrogen... 

Carbonylation of a trialkylborane in the presence of ethylene glycol promotes migration of both the second and third alkyl groups from the boron atom of intermediate X to the carbon atom derived from carbon monoxide. Subsequent oxidation by hydrogen peroxide in this case produces a tertiary alcohol which bears three substituents derived from the trialkylborane (Figure B3.4). 

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