Asymmetric synthesis of cyclic hydroxy ketones derived from enol ethers via sharpless asymmetric dihydroxylation. A study in the correlation of the enol ether chain length and enantioselectivity.
The Sharpless asymmetric dihydroxylation reaction of enol ethers derived from their corresponding cyclic ketones, gave alpha-hydroxyketones with high enantioselectivity. The enantiomeric excess was found to be proportional to the length of the unbranched enol ether chain with a maximum ee for the pentyl enol ether. An efficient synthesis of alpha-hydroxy chromanone in >90% ee was demonstrated using this method.
Marcune
Benjamin F
BF
Department of Process Research, Merck and Co., P.O. Box 2000, Rahway, New Jersey 07765, USA. ben_marcune@merck.com
Karady
Sandor
S
Reider
Paul J
PJ
Miller
Ross A
RA
Biba
Mirlinda
M
DiMichele
Lisa
L
Reamer
Robert A
RA