DEOXYRIBOSE-5-PHOSPHATE ALDOLASE AS A CATALYST IN ASYMMETRIC ALDOL CONDENSATION

This paper describes the substrate specificity and synthetic utility of deoxyribose-5-phosphate aldolase (DERA, EC 4.1.2.4). Eight donors and 20 acceptors have been tested as substrates. In addition to acetaldehyde, propanal, acetone, and fluoroacetone have been used to condense with a number of acceptor aldehydes. Thirteen aldol products have been prepared and characterized. A new stereogenic center with 3(S) configuration is formed when acetaldehyde, fluoroacetone, or acetone is used as a donor substrate. With propanal, two new stereogenic centers are formed with 2(R) and 3(S) configurations. The acceptor substrates have very little structural requirements. The 2-hydroxyaldehydes appear to react the fastest, and the D-isomers are better substrates than the L-isomers. The stereospecificity is absolute regardless of the chirality of 2-hydroxyaldehydes. The aldol reactions thus follow the Cram-Felkin mode of attack for D-substrates and anti-Cram-Felkin mode of attack for L-substrates.