Asymmetric Aza-[3 + 3] Annulation in the Synthesis of Indolizidines: An Unexpected Reversal of Regiochemistry
摘要:
An enantioselective and diastereoselective aza-[3 + 3] annulation of pyrrolidine-based exo-cyclic vinylogous amides and urethanes with chiral vinyl iminium salts is described. This asymmetric annulation manifold is possible because of an unexpected regiochemical reversal whereby head-to-tall annulations dominated over the predicted head-to-head. It should find prevalent synthetic applications in the enantioselective synthesis of indolizidines.
Asymmetric Aza-[3 + 3] Annulation in the Synthesis of Indolizidines: An Unexpected Reversal of Regiochemistry
摘要:
An enantioselective and diastereoselective aza-[3 + 3] annulation of pyrrolidine-based exo-cyclic vinylogous amides and urethanes with chiral vinyl iminium salts is described. This asymmetric annulation manifold is possible because of an unexpected regiochemical reversal whereby head-to-tall annulations dominated over the predicted head-to-head. It should find prevalent synthetic applications in the enantioselective synthesis of indolizidines.
Copper-Catalyzed Enantioselective Allyl-Allyl Coupling between Allylic Boronates and Phosphates with a Phenol/N-Heterocyclic Carbene Chiral Ligand
作者:Yuto Yasuda、Hirohisa Ohmiya、Masaya Sawamura
DOI:10.1002/anie.201605125
日期:2016.8.26
Copper‐catalyzedenantioselective allyl–allyl coupling between allylboronates and either Z‐acyclic or cyclic allylic phosphates using a new chiral N‐heterocycliccarbene ligand, bearing a phenolic hydroxy, is reported. This reaction occurs with exceptional SN2′‐type regioselectivities and high enantioselectivities to deliver chiral 1,5‐diene derivatives with a tertiary stereogenic center at the allylic/homoallylic
据报道,使用新的带有酚羟基的手性N-杂环卡宾配体,在烯丙基硼酸酯与Z-无环或环状烯丙基磷酸酯之间进行铜催化的对映选择性烯丙基-烯丙基偶联。该反应具有异常的S N 2'型区域选择性和高对映选择性,可在手性/均烯丙基位置以手性立体中心生成手性1,5-二烯衍生物。