The Configurational Correlation of Optically Active Biphenyls with Centrally Asymmetric Compounds. The Absolute Configuration of 6,6'-Dinitro-2,2'-diphenic Acid¹

Synthesis and chiroptical properties of bridged 2,2′-diaminobiphenyl derivatives

“…HCl to give the acid (6) as a powder (48.1 g, 87%) which was identical with an authentic sample. (7).-A suspension of (9-( -)-( 6) (3.5 g) and thionyl chloride (10 ml) in benzene (40 ml) was heated under reflux for 2 h. The volatile materials were removed by distillation under reduced pressure. The residue was dissolved in benzene (30 ml) and the solution was added to a stirred excess of diazomethane in ether at 5 "C. The solution was stirred for 1 h and concentrated under reduced pressure.…”

“…135") was synthesized as shown in Scheme 1. The Arndt-Eistert reaction of (8-( -)-(6) uia diazoketone (S)- (7) gave the homologated dicarboxylic acid (2948) in good yield. After catalytic hydrogenation of the nitro group, cyclization of the intermediate (9) to dilactam (10) was carried out at room temperature with dicyclohexylcarbodi-imide (DCC) in dilute solution.…”

Optical discrimination of racemic from achiral solutions

“…Since ee scales linearly with OR, 47,48 we calculate ee according to with a 0 determined from the fit of Fig. 3.…”

“…As mentioned in the introduction such a behavior is already known [34][35][36] and thus also theoretical approaches for kinetic modeling of ee are existent. In contrast to those 35,47,48 we describe the change in the number of molecules of the R-enantiomer upon RC illumination with first-order kinetics and combine that rate equation with diffusion into or out of the sample volume,…”

Recent development of asymmetric syntheses based on the Meerwein‐Ponndorf‐Verley reduction

“…Mislow and colleagues 13 observed a partial kinetic resolution of the dissymmetric biphenylic ketone, (±)-4Ј,1Љ-dinitro-1,2,3,4-dibenz-1,3-cycloheptadiene-6-one (DNDBCH-6-one) (4) (Scheme 4) by MPV reduction using centrally chiral alcohols. Treatment of (±)-DNDBCH-6-one (4) with (S)-(+)-pinacolyl alcohol or (S)-(+)-2-octanol in the presence of aluminum t-butoxide in dioxane gave, in each case, a mixture of (+)-DNDBCH-6-one (4) (72% ee, 31% ee) and (−)-DNDBCH-6-ol [(R)-5] (16% ee, 8% ee), respectively.…”