Substrate specificity and carbohydrate synthesis using transketolase
作者:Yoshihiro Kobori、David C. Myles、George M. Whitesides
DOI:10.1021/jo00048a023
日期:1992.10
This paper describes the use of the enzyme transketolase as a catalyst in organic synthesis. The properties of transketolase from both yeast and spinach were investigated. The yeast enzyme was found to be more convenient for routine use. Examination of the substrate specificity of yeast transketolase demonstrated that the enzyme accepts a wide variety of 2-hydroxy aldehydes as substrates. A practical protocol for transketolase-catalyzed condensation of hydroxypyruvic acid with these aldehydes has been developed and used for the synthesis of four carbohydrates: L-idose, L-gulose, 2-deoxy-L-xylohexose, and L-xylose.
Diastereoselectivity (enantioselectivity) of aldol condensations catalyzed by rabbit muscle aldolase at C-2 of RCHOHCHO if R has an appropriately placed negatively charged group
作者:Watson J. Lees、George M. Whitesides
DOI:10.1021/jo00059a047
日期:1993.3
D-Fructose 1,6-bis(phosphate) aldolase from rabbit muscle (RAMA, E.C. 4.1.2.13) catalyzes the aldol condensation between dihydroxyacetone phosphate (DHAP) and various aldehydes; the products are ketosugars with 3(S),4(R) stereochemistry. When racemic alpha-hydroxy aldehydes are condensed with DHAP, two diastereomeric products are formed. This paper demonstrates that RAMA can kinetically resolve alpha-hydroxy aldehydes with a negative charge removed four or five atoms from the aldehydic center. Kinetic resolution of either uncharged alpha-hydroxy aldehydes, or of alpha-hydroxy aldehydes with a negative charge removed three or seven atoms from the aldehydic carbon, is generally not as successful.
SHONO, TATSUYA;MATSUMURA, YOSHIHIRO;INOUE, KENJI;IWASAKI, FUMIAKI, J. CHEM. SOC. PERKIN TRANS., 1986, N 1, 73-77