Total Synthesis of (−)-Tetrahydropalmatine via Chiral Formamidine Carbanions: Unexpected Behavior with Certain Ortho-Substituted Electrophiles
作者:Mark A. Matulenko、A. I. Meyers
DOI:10.1021/jo951611q
日期:1996.1.1
established using an ortho-substituted hydroxymethylbenzene electrophile protected as a silyl ether to ultimately provide (-)-tetrahydropalmatine in 88% ee. Additionally, we have discovered limitations with ortho-substituted electrophiles in the asymmetric formamidine alkylation. These electrophiles have the potential to disrupt the lithium formamidine chelate and cause the selectivity in the alkylation to
已经开发出一种通过手性硫代甲alkyl的烷基化来构建具有C(9)和C(10)D环取代模式的原小ber碱生物碱的方法。使用被保护为甲硅烷基醚的邻位取代的羟甲基苯亲电子试剂建立该环型,以最终提供88%ee的(-)-四氢巴马汀。此外,我们发现在不对称甲am烷基化反应中邻位取代的亲电试剂存在局限性。这些亲电试剂具有破坏甲form酸锂螯合物的潜力,并导致烷基化反应的选择性异常低。本文描述了(+/-)-犬精和(-)-四氢巴马汀的总合成以及对甲am烷基化技术的限制。