Isopropyl glyoxylate

A simple chiral silane [(13), 2 1 mixture of diastereoisomers] mediates the enan-tioselective reaction of electron-rich arenes and heteroarenes with the benzoylhydra-zone of isopropyl glyoxylate under optimized conditions, leading to a useful synthesis... 

In a similar fashion, Achmatowicz et al. have studied the cycloaddition of 1-acetoxy- and l-trimethylsilyloxy-3-methyl-l,3-butadiene with diethyl oxoma-lonate and isopropyl glyoxylate under thermal and high pressure conditions [542],... 

Et ester, semicarbazone Mp 228°. Isopropyl ester Isopropyl glyoxylate [924-53-8]... 

Isopropyl 6-amino-6-deoxy-a-L-idopyranoside, A-294 Isopropyl 6-amino-6-deoxy-p-L-idopyranoside, A-294 Isopropyl glucosinolate, 1-57 Isopropyl glyoxylate, G-559... 

Intramolecular asymmetric induction has also been used in electrochemistry as in the reduction of optically active alcohol esters or amides of a-keto [469,470] and unsaturated [471] acids and oximes [472] and in the oxidation of olefins [473]. A maximum asymmetric yield of 81% was obtained in the reduction of (5 )-4-isopropyl-2-oxazolidinone phenyl-glyoxylate [470]. Nonaka and coworkers [474,475] found that amino acid A-carboxy anhydrides were polymerized with various electrogenerated bases as catalyst to give the poly(amino acids) with high chirality in high yields. Conductive chiral poly(thiophenes) prepared by electropolymerization can be used for chiral anion recognition [476]. 

The tritylation of 5 was performed in pyridine using standard procedures. Reaction mixtures were worked-up by water quenching followed by filtration and recrystallization of the crude product. Recrystallization of the crude product was done from 2-propanol containing small amounts of triethylamine. The addition of triethylamine was necessary to avoid the formation of trityl isopropyl ether by solvolysis of the product when heated in 2-propanol. The yield of the product in this step was 75-80%. Impurities such as ethyl glyoxylate diethyl acetal carried over from previous steps were removed during the isolation of 6. 

Carbonyl compounds include isobut3raldehyde, phenyl isopropyl ketone, glyoxylic acid and pyruvic acid. Diaryl ketones do not react. Modifications of the method consist in the use of a borohydride exchange-resin, of sodium triacetoxyborohydride NaBH(OAc)3 or in treating a mixture of a ketone and an amine with an equivalent of titanium(IV) chloride and Hiinig s base (ethyldiisopropylamine) in dichloromethane, followed by a methanolic solution of sodium cyanoborohydride. The borane-pridine complex and hydrogen telluride are excellent replacanents for sodium cyanoborohydride. 

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