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Updated: Aug 5, 2026

Microwave-assisted Intramolecular Dehydrogenative Diels-Alder Reactions for the Synthesis of Functionalized Naphthalenes/Solvatochromic Dyes
Published on: April 1, 2013
A convenient chemoenzymatic synthesis of (4aS,5S)-(+)-4,4a,5,6,7,8-hexahydro-5-hydroxy-4a-methylnaphthalen-2(3H)-one
Lee-Chiang Lo1, Jung-Jing Shie, Tzyy-Chao Chou
1Department of Chemistry, National Taiwan University, Taipei 106, Taiwan. lclo@ccms.ntu.edu.tw
Abstract:
We have developed a convenient chemoenzymatic method for the preparation of (4aS,5S)-4,4a,5,6,7,8-hexahydro-5-hydroxy-4a-methylnaphthalen-2(3H)-one by taking advantage of the excellent enantioselectivity of alcalase. Four different esters were compared, and the butanoate ester was found to be the best substrate. The stereochemistry of the product is the same as the one predicted from the binding model of alcalase. A simple extraction/partition procedure was used to separate the hydroxyenone product from the remaining ester. This practical procedure would be very useful in a gram-scale operation for securing the title compound in high optical purity.
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