4603-32-1Relevant academic research and scientific papers
Formation and fragmentation of 4-diazo-1,2-diphenyl-3-oxo-butyl acetate
Oezbilen, Deniz,Beile, Bernhard,Meier, Herbert
, p. 99 - 102 (2013/04/10)
Threo-4-Diazo-1,2-diphenyl-3-oxo-butyl acetate (15) could be prepared via the classical route 6 → 8 → 10 → 12 → 13 → 15. However, its alkaline hydrolysis to the bifunctional hydroxy compound 17 led to a spontaneous dehydration to the diazoketone (E)-18 and to a fragmentation to acetic acid, benzaldehyde (8) and diazoketone 19.
On the Stereochemistry of Lignin Model Compounds of the 1,2-Diaryl-1,2-propanediol Type. The Crystal Structure of erythro-2-(4-Methoxyphenyl)-1-phenyl-1,3-propanediol
Lundquist, Knut,Stomberg, Rolf
, p. 610 - 616 (2007/10/02)
Properties (location of 1H NMR signals, stability of borate complexes) of diastereomers of legnin-related diarylpropanediols are discussed. 1H NMR spectral comparisons with the threo and erythro forms of 1,2-diphenyl-1,3-propanediol provide a basis for the assignments of diastereomers of lignin model compounds of the 1,2-diaryl-1,3-propanediol typy.Final confirmation of the structure of such a compound, erythro-2-(4-methoxyphenyl)-1-phenyl-1,3-propanediol, was achieved by a single-crystal X-ray analysis.This compound crystallizes in the monoclinic space group P21 with a=8.703(4), b=6.060(2), c= 13.487(6) Angstroem, β=99.84(4) deg and Z=2.The structure was determined by direct methods.Least-squares refinement gave R=0.039 for 1311 observed independent reflections.
STEREOSELECTIVE ADDITIONS TO CARBOXYLIC ACID DIANIONS AND β-LACTONE SUBSTITUTED ESTER ENOLATES. APPLICATION TO THE SYNTHESIS OF RACEMIC EPI-BLASTMYCINONE, δ-MULTISTRIATINE, PARACONIC ESTERS AND LIGNANTYPE DILACTONES
Mulzer, Johann,Lasalle, Peter de,Chucholowski, Alexander,Blaschek, Ursula,Bruentrup, Gisela,et al.
, p. 2211 - 2218 (2007/10/02)
New stereoselective syntheses are reported for racemic 4-epi-blastmycinone (6) and δ-multistriatine (13) utilizing the anti-configurated γ,δ-unsaturated β-hydroxy-carboxylic acids 2a/b.A diastereo- and enantioselective aldoltype addition of phenylacetic acid dianion to benzaldehyde has been achaived by employing optically active alkoxide amide bases.Finally, highly stereocontrolled additions to the novel β-lactone substituted ester enolates 22 are described.
Stereochemistry of the Addition of Carboxylic Acid Dianions to Aldehydes under Kinetic and Thermodynamic Control - Synthesis and Configurational Assignment of 2,3-Disubstituted threo- and erythro-3-Hydroxycarboxylic Acids
Mulzer, Johann,Zippel, Matthias,Bruentrup, Gisela,Segner, Johannes,Finke, Juergen
, p. 1108 - 1134 (2007/10/02)
Under kinetically controlled conditions (-50 deg C, 10 min) the carboxylic dianions 2 add to aldehydes 3 to give the threo/erythro-adducts 4/5 (Scheme 1); the threo-selectivity markedly increases with the bulkiness of the substituents of 2 or 3 and decreases with the charge/radius ratio of the counter-ions of 2.From these results a syn-transition state with a HOMO-LUMO ineraction between 2 and 3 is derived (Scheme 3).For appropriate substituents a far higher threo-selectivity is observed under thermodynamically (22-50 deg C, 1-3 days) than under kinetically controlled conditions.We describe the isolation of the hydroxy acids 6 and 7, which are formed from 4 and 5 on acidic hydrolysis, and show how their configurations can be unambiguously assigned on the basis of 1H-NMR data.
