Stereodivergent Synthesis of the C1-C9 Tetrahydropyran Subunit of Zincophorin and Isomers Thereof
作者:Yvan Guindon、François Godin、Ioannis Katsoulis、Émilie Fiola-Masson、Sabrina Dhambri、Philippe Mochirian
DOI:10.1055/s-0031-1289661
日期:2012.2
diastereoselectively by sequential iodoetherification and radical hydrogen-transfer reactions. Stereoselective formation of 3,7-trans or 3,7-cis rings was rationalized through minimization of allylic-1,3 strain in chair-like transition states. Subsequent hydrogen-transfer provided 7,8-anti or 7,8-syn isomers under acyclic stereocontrol or endocyclic control respectively. The latter approach relies on the formation
通过连续的碘醚化和自由基氢转移反应,非对映选择性地制备了Zincophorin C1-C9片段和七个四氢吡喃类似物。3,7-反式或3,7-顺式环的立体选择性形成通过在椅子状过渡态下最小化allyal-1,3应变来合理化。随后的氢转移分别在无环立体控制或内环控制下提供了7,8-抗或7,8-顺式异构体。后一种方法依赖于由双齿路易斯酸螯合四氢吡喃环的氧和酯而形成的[4.4.0]双环配合物。 离子载体-碘醚化-自由基还原-路易斯酸-取代的四氢吡喃