Five and six: 3,4‐Cyclopentyl‐ and cyclohexyl‐fused 2‐arylchromans could be readily prepared from the intramolecular hetero‐Diels–Alder reactions of the corresponding ortho‐quinone methide (o‐QM) precursors tethered to the styrenes under mild reaction conditions. The products were obtained with good to excellent diastereoselectivity (up to>99:1 dr; see scheme; MOM=methoxymethyl).
五和六种化合物:3,4-环戊基和环己基稠合的2-芳基苯并二氢
吡喃可以很容易地从温和反应下与邻苯醌甲基化物(o- QM)前体的分子内杂Diels-Alder反应中制得情况。获得具有良好至优异的非对映选择性的产物(高达> 99:1 dr;参见方案; MOM =甲氧基甲基)。