An efficient dipeptide-catalyzed direct asymmetric aldol reaction of equimolar reactants in solid media.
The direct asymmetric aldol reactions of equivalent molar amounts of aldehydes and ketones were carried out at -20 degrees C over alkaline Al(2)O(3) with 20 mol % of Pro-Trp as catalyst and 20 mol % of N-methylmorpholine or 1,4-diazabicyclo[2.2.2]octane as additive. After simple and environmentally friendly work-up, moderate to high isolated yields (up to 95%), good diastereoselectivities (>99:1), and enantioselectivities (up to 98% ee) have been achieved for the reactions of different kinds of ketones with various aldehydes. The catalytic system could be reused without decrease of activity by addition of 10 mol % catalyst and base in the catalytic system.
Lei
Meng
M
State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, China.
Xia
Shuai
S
Wang
Junfeng
J
Ge
Zemei
Z
Cheng
Tieming
T
Li
Runtao
R
D000447:Aldehydes / Q000737:chemistry*; D000537:Aluminum Oxide / Q000737:chemistry; D002384:Catalysis; D004151:Dipeptides / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry*
D000447:Aldehydes; D004151:Dipeptides; D007659:Ketones; D000537:Aluminum Oxide