Oxidative Catalysis Using the Stoichiometric Oxidant as a Reagent: An Efficient Strategy for Single-Electron-Transfer-Induced Tandem Anion-Radical Reactions
Oxidative single‐electrontransfer‐catalyzed tandem reactions consisting of a conjugate addition and a radical cyclization are reported, which incorporate the mandatory terminal oxidant as a functionality into the product.
Nonproteinogenic amino acids are prepared by an unprecedented domino aza-Michael addition-1,3-dipolar cycloaddition, leading to enantiopure highly substituted pyrrolidinopyrazolines. Nonaflyl azide serves as highly effective diazo transfer reagent, forming the link between the conjugate addition and cycloaddition steps. The resulting pyrrolidinopyrazolines can be rapidly transformed to either alpha,beta,gamma-triamino acids or 3,4-methano-beta-prolines. Peptide coupling can be regioselectively conducted at each of the amino groups.
<i>N</i>,2,3,4-Tetrasubstituted Pyrrolidines through Tandem Lithium Amide Conjugate Addition/Radical Cyclization/Oxygenation Reactions
Enantioselective syntheses of densely functionalized pyrrolidines deriving their chirality from (R)-1-(phenyl)ethylamine are reported. Allylic amines and β-substituted-α,β-unsaturated esters are used as the building blocks in this one-pot reaction. Single electron transfer (SET) oxidation served to merge the reactivities of anionic enolate and radical intermediates. Ferrocenium hexafluorophosphate
报告了从 (R)-1-(苯基) 乙胺衍生其手性的密集官能化吡咯烷的对映选择性合成。烯丙胺和 β-取代-α,β-不饱和酯用作该一锅反应的构建单元。单电子转移 (SET) 氧化有助于合并阴离子烯醇化物和自由基中间体的反应性。易于制备、储存和处理的二茂铁六氟磷酸被用作 SET 氧化剂,持久性自由基 TEMPO 用作氧化剂,引入受保护的羟基官能团,这被证明有利于进一步衍生。在目标四取代吡咯烷中实现了独有的 2,3-反式和高达 6:1 的 3,4-顺式/反式非对映选择性。