1579-16-4

Regioselective hydrogenation of 1,2-indanedione yielding rac-2-hydroxy-1-indanone was investigated using heterogeneous Pt and Pd as catalysts. Five consecutive experiments were carried out for studying the performance of Pd/Al2O3. Pr

Optically active β-amino alcohols are very useful chiral intermediates frequently used in the preparation of pharmaceutically active substances. Here, a novel cyclohexylamine oxidase (ArCHAO) was identified from the genome sequence of Arthrobacter sp. TYUT010-15 with the R-stereoselective deamination activity of β-amino alcohol. ArCHAO was cloned and successfully expressed in E. coli BL21, purified and characterized. Substrate-specific analysis revealed that ArCHAO has high activity (4.15 to 6.34 U mg?1 protein) and excellent enantioselectivity toward the tested β-amino alcohols. By using purified ArCHAO, a wide range of racemic β-amino alcohols were resolved, (S)-β-amino alcohols were obtained in >99 % ee. Deracemization of racemic β-amino alcohols was conducted by ArCHAO-catalyzed enantioselective deamination and transaminase-catalyzed enantioselective amination to afford (S)-β-amino alcohols in excellent conversion (78–94 %) and enantiomeric excess (>99 %). Preparative-scale deracemization was carried out with 50 mM (6.859 g L?1) racemic 2-amino-2-phenylethanol, (S)-2-amino-2-phenylethanol was obtained in 75 % isolated yield and >99 % ee.

Enantiomerically pure cis-glycols, derived through the microbial metabolism of hydrocarbons, represent a valuable chiral pool for the synthesis of cis β-amino alcohols. One generally applicable route to these important chiral intermediates is described. Reaction of the metabolically formed diol with α-acetoxyisobutyryl chloride affords regio- and stereoselectively a single trans-1,2-chlorohydrin acetate isomer. Displacement of chloride by azide, aminolysis of the ester and reduction of the azide provides the requisite amino alcohols. This 4-step route is highly efficient and affords the cis β-amino alcohol enantiomers in 41-57% overall yields. Using the highly enantiopure amino alcohols diastereomeric oxazaborolidines were prepared with both (-)-(S)- and (+)-(R)-[2-(1-methoxyethyl)phenyl]boronic acids. As described herein, these derivatives are potentially useful for absolute configurational assignments to cis amino alcohols.

The photochemistry of enol esters 1 is dominated by electrocyclic ring opening (1b → 3+4), 1,3-acyl migration (1c,d → 6c,d) and [2 + 2] dimerization (1d → 11). Photosensitization with triphenylpyrylium tetrafluoroborate (TPT) enhances formation of oxidation products (1b → 5,1c,d → 9c,d + 10c,d), presumably through the intermediacy of radical cations 1b-d+.

Xenon difluoride (XeF2) reacts with indene in 1,2-dimethoxyethane-water (90:10) to give cis- and trans-2-fluoro-1-hydroxyindans.Our data indicate that neither xenon oxide (XeO) nor hydroxyxenon fluoride (HOXeF) is an intermediate in this reaction even though XeO is a suspected intermediate from aqueous hydrolysis of XeF2.