Iterative Organometallic Addition to Chiral Hydroxylated Cyclic Nitrones: Highly Stereoselective Syntheses of α,α‘- and α,α-Substituted Hydroxypyrrolidines
作者:Andrea Goti、Stefano Cicchi、Vanni Mannucci、Francesca Cardona、Francesco Guarna、Pedro Merino、Tomas Tejero
DOI:10.1021/ol035798g
日期:2003.10.1
see text]. Iteration of organometallic addition to chiral hydroxylated pyrroline N-oxides through an addition-oxidation-addition synthetic sequence allowed highly stereoselective double alkylation of pyrrolidine at C-2 or at C-2 and C-5 depending on the regioselectivity of the oxidation step. Application of this methodology has been exemplified by the synthesis of the all-substituted pyrrolidine alkaloid
[反应:请参见文字]。通过加成-氧化-加成合成序列对有机金属加成至手性羟基化的吡咯啉N-氧化物的迭代使得吡咯烷在C-2或在C-2和C-5具有高度立体选择性的双烷基化,这取决于氧化步骤的区域选择性。该方法的应用已通过合成全取代的吡咯烷生物碱(-)-codonopsinine和具有可控制立体构象中心的脯氨酸型氨基酸前体得到了例证。