Premium
Synthesis of 4‐Hydroxy‐5‐methyl‐ and 4‐Hydroxy‐6‐methylcyclohexenones by Pd II ‐Catalyzed Oxidation and Lipase‐Catalyzed Hydrolysis
Author(s) -
Meister Anne C.,
Nieger Martin,
Bräse Stefan
Publication year - 2012
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201200704
Subject(s) - chemistry , diastereomer , regioselectivity , enone , catalysis , lipase , candida rugosa , hydrolysis , allylic rearrangement , enantiomer , organic chemistry , palladium , enzyme
A short route for the syntheses of methyl‐substituted hydroxycyclohexenones, which are building blocks for various natural products, is presented. Both oxygen atoms were introduced as acetates by a palladium(II)‐catalyzed 1,4‐addition to a 1,3‐diene. The distinction between the two acetoxy groups was achieved by regioselective monohydrolysis with lipase from Candida rugosa , which gave 1‐acetoxy‐4‐hydroxy‐5‐methylcyclohexene and its 6‐methyl regioisomer as a separable mixture. The target compounds 4‐hydroxy‐5‐methylcyclohex‐2‐enone and 4‐hydroxy‐6‐methylcyclohex‐2‐enone could then be obtained as diastereomeric mixtures in good overall yields and with moderate enantiomeric excesses (31–67 %).