Lipase-mediated resolution of substituted 2-aryl-propanols: application to the enantioselective synthesis of phenolic sesquiterpenes
摘要:
A comprehensive study of the lipase-mediated resolution of substituted 2-aryl-propanols is reported. The latter alcohols were submitted to the irreversible acetylation catalyzed either by PPL, CRL, or lipase PS. The enantioselectivity of these transformations was dependent on the type of lipase used. The type of substituents and particularly their position on the aromatic ring strongly affected the selectivity of the reaction. The experiments described prove that PPL is the more versatile lipase catalyzing the acetylation with an enantiomeric ratio (E) value that ranges from 1 up to 144, depending on the substrate used. Conversely, the same transformations were catalyzed by CRL and lipase PS with an enantiomeric ratio value, which is always less than 5. The remarkable behavior of PPL was exploited in the large scale resolution of some substituted 2-aryl-propanols whose enantiomeric forms are relevant building blocks in the enantioselective synthesis of phenolic sesquiterpenes. By these means, the synthesis of (S)-turmeronol B and the formal syntheses of (R)-curcumene, (R)-curcuphenol, (R)-xanthorrhizol, and (R)-curcuhydroquinone were accomplished. (C) 2011 Elsevier Ltd. All rights reserved.
Highly diastereoselective Michael addition of lithium diorganocuprates to the half-ester of 1, 1'-binaphthalene-8, 8'-diol gave β-substituted esters with high enantiomeric excess after methanolysis. The optically active phenolic sesquiterpenes turmeronol A (1) and B(2) have been synthesized using this reaction as a key step.
二愈创木酸锂与 1,1'-联萘-8,8'-二醇的半酯进行高非对映选择性迈克尔加成反应,甲醇分解后得到对映体过量的 β-取代酯。以该反应为关键步骤,合成了具有光学活性的酚类倍半萜化合物松柏醇 A (1) 和 B(2)。
Lipase-mediated resolution of substituted 2-aryl-propanols: application to the enantioselective synthesis of phenolic sesquiterpenes
作者:Stefano Serra
DOI:10.1016/j.tetasy.2011.03.012
日期:2011.3
A comprehensive study of the lipase-mediated resolution of substituted 2-aryl-propanols is reported. The latter alcohols were submitted to the irreversible acetylation catalyzed either by PPL, CRL, or lipase PS. The enantioselectivity of these transformations was dependent on the type of lipase used. The type of substituents and particularly their position on the aromatic ring strongly affected the selectivity of the reaction. The experiments described prove that PPL is the more versatile lipase catalyzing the acetylation with an enantiomeric ratio (E) value that ranges from 1 up to 144, depending on the substrate used. Conversely, the same transformations were catalyzed by CRL and lipase PS with an enantiomeric ratio value, which is always less than 5. The remarkable behavior of PPL was exploited in the large scale resolution of some substituted 2-aryl-propanols whose enantiomeric forms are relevant building blocks in the enantioselective synthesis of phenolic sesquiterpenes. By these means, the synthesis of (S)-turmeronol B and the formal syntheses of (R)-curcumene, (R)-curcuphenol, (R)-xanthorrhizol, and (R)-curcuhydroquinone were accomplished. (C) 2011 Elsevier Ltd. All rights reserved.