Efficient and flexible synthesis of chiral gamma- and delta-lactones.
An efficient and highly flexible synthesis for chiral gamma- and delta-lactones with high enantiomeric purity is described (>99% ee and 57-87% overall yield). The protocol involves alkylation of chiral 1,2-oxiranes with terminally unsaturated Grignard reagents. Subsequent oxidative degradation (OsO(4)-Oxone) of the terminal double bond from chiral alk-1-en-5-ols and alk-1-en-6-ols affords 4- or 5-hydroxy acids and gamma- and delta-lactones after acidic workup. The flexibility and efficiency of the protocol is illustrated by the synthesis of several alkanolides and alkenolides, hydroxy fatty acids and dihydroisocoumarins.
Habel
Andreas
A
Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str.8. 07745-Jena, Germany.
Boland
Wilhelm
W
D000478:Alkylation; D005027:Ethylene Oxide / Q000737:chemistry; D006880:Hydroxy Acids / Q000737:chemistry; D007783:Lactones / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry; D010084:Oxidation-Reduction; D013237:Stereoisomerism
D006880:Hydroxy Acids; D007783:Lactones; D009942:Organometallic Compounds; D005027:Ethylene Oxide