33’-Biphenyl diol

The catalytic asymmetric epoxidation of a,/i-unsaturated carbonyl compounds is one of the synthetically useful reactions in organic synthesis.The resulting chiral epoxides are easily converted to various useful chiral compounds. We developed a new yttrium-(5)-6,6 -[oxybis(ethylene)dioxy]biphenyl-2,2 -diol (1) (Figure 6.10)... 

SYNTHESIS OF (5)-6,6 -[OXYBIS(ETHYLENE)DIOXY]BIPHENYL-2,2 -DIOL(l)... 

A 10 mL round-bottomed flask was charged with (5)-6,6 -[oxybis(ethylene) dioxy]biphenyl-2,2 -diol (1) (98% ee, 225.6 mg, 0.78 mmol), quinine (127.0 mg, 0.39 mmol) and ethanol (2mL). The mixture was warmed until the mixture suspension turned to a clear solution, and was allowed to settle for 12 h. The solid residue [crystals of (5)-l-quinine complex] was collected by filtration. To a mixture of aqueous 1 M HCl and ether was added the obtained crystals of (5 )-l-qumine complex. This was stirred for 15 min at room temperature, and the solution was extracted with ether (twice). The combined organic layers were washed with brine, and dried over sodium sulfate. After concentration in vacuo, the residue was purified by silica gel flash column chromatography (hexane/ethyl acetate = 20/1-3/1) to give optically pure (5)-l (167.8 mg, 74%, 99% ee) as a colourless solid. The enantiomeric excess of (5)-l was determined by chiral stationary-phase HPLC analysis DAICEL CHIRALCEL... 

Condensation of biphenyl-2-2 -diols with the appropriate sulfur, phosphorus, or silane-dichloride to give the corresponding dibenzo[organic base present, as exemplified in Table 15. Similarly, the dioxaboracin (49) is obtained by dehydrative cyclization of the bisphenol with phenylboric acid. 

By using identical compounds and reactions, bnt in which the tert-bulyl group is replaced by a 1-adarrrarrlyl group the corresponding 1-adamantyl (H2BIAD) derivatives are obtained in almost sirrtilar yields arrd rrsed to prepare related molybdenum catalysts. Eor example (S)-3 -bls(l-adamaiityl)-5, 6,6 -tetramethyl-l,l -biphenyl-2,2 -diol (S)-H2(BIAD) S-(-)-3,3 -biphenyl-2 -dlol, 5, 6,6 -tetramethyl-3 -bis(tricyclo-... 

Dihydroxybiphenyl CAS 1806-29-7 EINECS/ELINCS 217-303-0 Synonyms 2,2 -Biphenol o,o -Biphenol [1,1 -Biphenyl]-2,2 -diol 2,2 -Biphenyldiol Biphenyl-2,2 -diol... 

The stereochemistry at the chiral centres of the three new lignans, erythro-strebluslignanol, threo-T-methoxyl strebluslignanol and erythro-T-meth-oxyl strebluslignanol has been established by Li et al by analysis of vicinal proton-proton couplings as well as CD spectra and optical rotation data. The determined chemical structures of these compounds were (7 R,8 5)-5-allyl-5 -(l,2-dihydroxypropyl)[l,l -biphenyl]-2,2 -diol, (7 R,8 R)-5-allyl-5 -(2-hydroxy-l-methoxypropyl)[l,l-biphenyl]-2,2 -diol and (7 R,8 5)-5-allyl-5 -(2-hydroxy-l-methoxypropyl)[l,l-biphenyl]-2,2 -diol. 

The molybdenum complex of 1,1 -biphenyl-2,2 -diol-based ligand (BIPHEN) possessing an axial element of chirality proved to be an efficient catalyst in various modes of enantioselective olefin metathesis (71). (The catalytic precursor is known as the Schrock-Hoveyda catalyst.)... 

Dimethoxy-5,5 -di-2-propenyl[l,r-biphenyl -2,2 -diol, 9Cl. 5,5 -Diallyl-2,2 -dihydroxy-3,3 -dimethoxybiphenyl. 6 -4,4 -Dihydroxy-5,5 -dimethoxy-3,3 -neolignan. 

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