The first enantioselective total syntheses of the β-carboline alkaloids (â)-isochrysotricine (1) and (â)-isocyclocapitelline (2) are reported which confirm the absolute configuration of these natural products. Key steps are the copper-mediated SN2â²-substitution of propargyl oxiranes13/14 and the gold-catalyzed cycloisomerization of α-hydroxyallene 15, resulting in a highly efficient center-to-axis-to-center chirality transfer.
β-咔啉
生物碱 (α)-isochrysotricine (1) 和 (α)-isocyclocapitelline (2) 的第一个对映选择性全合成被报道,证实了这些
天然产物的绝对构型。关键步骤是
铜介导的炔
丙基环氧乙烷13/14的SN2-取代和
金催化的α-羟基
丙二烯15的环异构化,从而产生高效的中心到轴到中心的手性转移。