A convenient method for obtaining trans-2-aminocyclohexanol and trans-2-aminocyclopentanol in enantiomerically pure form

Abstract

The conversion of syn-(methy1,hydro)bimane (1) to products was between 50% and loo%, based on the recovery of 1. The yields of 2 were between 25% and 30%, of 3 between a trace and 5%, and of 4 from 50% to 60%.Kinetic Measurements. syn-(CH,,F)B (2) was dissolved in CH3CN. An aliquot (100 pL) was added rapidly to aqueous buffer, pH 10.2, maintained at 50.0 "C in a thermostated quartz cell located in the cell compartment of a Cary 17 spectrophotometer. The decrease of absorption at 360 nm was followed with time for more than 10 half-lives. The second-order rate constant for the reaction of the bimane with hydroxide ion was obtained from the experimental curve from the slope of the plot of log (Dt -Dinf) vs. time and dividing by the temperature corrected hydroxide ion concentration.Regeneration of 2 from the Pyrazolinoylacrylic Acid. A mixture of the acid (obtained from base-catalyzed ring opening of syn-(CH,,F)B and acidification) (1 mg) and thionyl chloride (10 rL) was stirred for 24 h. After removal of thionyl chloride under vacuum, the residue was shown to be identical with authentic syn-(CH,,F)B (2) in absorption maximum (340 nm; dioxane), emission maximum (433 nm; dioxane), and thin-layer chromatographic behavior.Acknowledgment. The aid of M. Ben-Shoshan and Y. Menachem in preparing the syn-(CH3,H)B is acknowledged.

The First Asymmetric Halogen/Metal‐Exchange Reaction: Desymmetrization of Alcohols with Enantiotopic Bromoarene Substituents

“…Alcohols 11 and 12 as well as aminoalcohol 14 and (S)-2,2'-dihydroxy-1,1'-binaphthalene [(S)-BINOL (17 a)] were purchased. Aminoalcohols 13 a, [17] 13 b, [18] 13 c, [19] 13 d, [20] 15 a, [21] 15 b, [22] 16 a, [23] and 16 b [24] were prepared according to literature procedures, and (S)-BINOL-monoethers 17 b [25,26] and 17 c, d as well. [26] NHC precursor 21 is an elaborated 2-amino-2'-hydroxy-1,1'-binaphthalene (NOBIN) and was obtained by our recently developed synthesis [27] in 55 % overall yield, avoiding the lengthier previous synthesis.…”

Enantioselectively functionalised phenytoin derivatives by auxiliary-directed N to C aryl migration in lithiated α-amino nitriles

“…Trans-2-aminocyclohexanol has been used as a chiral auxiliary or chiral ligand in a number of other reactions, [12] and both enantiomers are commercially available and equally accessible on scale from amination of the corresponding meso epoxide. [12,13] The auxiliary may be easily removed under acidic conditions by dehydration -enamide hydrolysis. Extension of the highly diastereoselective rearrangement of 6e to other substrates would constitute a method for the synthesis of enantiomerically enriched 5,5-diaryl hydantoins related to the anti-convulsant drug phenytoin, selectively functionalised on one of the two phenyl rings.…”

Chiral 1,2-Amino Alcohols and 1,2-Diamines Derived from Cyclohexene Oxide: Recent Applications in Asymmetric Synthesis

“…A pioneering report of the synthesis of enantiopure cyclic 1,2-amino alcohols is due to Overman et al 5 who carried out the ambient temperature aminolysis of meso-epoxides 1a and 1b with aluminum amide 3, in nearly quantitative yield. The aluminum amide 3 was formed from (R)-1-phenylethylamine, (R)-2, and trimethylaluminum affording mixtures of the diastereomeric trans-2-amino-cycloalkanols 4-7 from cyclopentene oxide 1a and cyclohexene oxide 1b (Scheme 1).…”