Diastereoselective Construction of <i>trans</i>-2-Alkyl-6-aryl-3,6-dihydro-2<i>H</i>-pyrans via Dehydrogenative Cycloetherification Promoted by DDQ
作者:Heesun Yu、Ryangha Lee、Hyoungsu Kim、Dongjoo Lee
DOI:10.1021/acs.orglett.1c00154
日期:2021.2.5
A diastereoselective synthesis of trans-2-alkyl-6-aryl-3,6-dihydro-2H-pyrans has been described. Dehydrogenative cycloetherification of (E)-(±)-1-aryl-5-hydroxy-1-alkenes promoted by DDQ proceeded cleanly via 6-endo cyclization to afford trans-2-alkyl-6-aryl-3,6-dihydro-2H-pyrans (32 examples) in good yield (up to 89%) and with moderate to excellent diastereoselectivity (up to 99:1). The synthetic
的非对映选择性合成反式-2-烷基-6-芳基- 3,6-二氢-2- ħ -pyrans进行了说明。的(脱氢cycloetherification ë) - (±)通过DDQ促进-1-芳基-5-羟基-1-烯烃经由-6-干净地进行内切的环化,得到反式-2 -烷基-6-芳基- 3,6-二氢2 H-吡喃(32个实例),收率好(高达89%),非对映选择性中等(至99:1)。该方法的合成效用通过(±)-(2 R,6 S)-3,4-脱氢-1,7-双(4-羟基苯基)-4'-de- O的第二次全合成来说明-甲基中心洛宾和(±)-中心洛宾的总合成。