A New Palladium-Catalyzed Intramolecular Allylation to Pyrrolidin-2-ones<sup>1</sup>
作者:Giuliano Giambastiani、Barbara Pacini、Marina Porcelloni、Giovanni Poli
DOI:10.1021/jo971849+
日期:1998.2.1
A novel palladium(0)-catalyzed cyclization to 3,4-disubstituted pyrrolidin-2-ones has been developed. The new approach relies upon the concomitant generation of stabilized acetamide enolate anions and of a pi-allyl-palladium appendage, properly tethered by a nitrogen atom. Reaction conditions have been optimized for the methoxycarbonyl-stabilized model reaction [(Z)-2 --> 3] and then applied to other
γ- and δ-Lactams through Palladium-Catalyzed Intramolecular Allylic Alkylation: Enantioselective Synthesis, NMR Investigation, and DFT Rationalization
作者:Xavier Bantreil、Guillaume Prestat、Aitor Moreno、David Madec、Peter Fristrup、Per-Ola Norrby、Paul S. Pregosin、Giovanni Poli
DOI:10.1002/chem.201001300
日期:2011.3.1
give γ‐ and δ‐lactams has been studied in the presence of chiral ligands. Ligand (R)‐3,5‐tBu‐MeOBIPHEP (MeOBIPHEP=6,6’‐dimethoxybiphenyl‐2,2‐diyl)bis(diphenylphosphine)) afforded the best results and allowed the cyclization reactions to take place in up to 94:6 enantiomeric ratio. A model Pd–allyl complex has been prepared and studied through NMR spectroscopic analysis, which provided insight into the
在手性配体存在下,对钯催化的不饱和酰胺的分子内烯丙基烷基化反应生成γ-和δ-内酰胺进行了研究。配体(R)-3,5- t Bu-MeOBIPHEP(MeOBIPHEP = 6,6'-二甲氧基联苯-2-2,2-二基)双(二苯基膦))提供了最佳结果,并使环化反应可在多达94个条件下进行:6对映体比率。制备了钯-烯丙基复合物模型,并通过NMR光谱分析进行了研究,该分析提供了对观察到的对映体比率负责的过程的见解。DFT研究用于表征非对映异构反应途径。计算出的能量差与实验观察到的对映体比率非常吻合。
Palladium-catalyzed intramolecular allylic alkylations of unsaturated EWG-activated amides can take place under phase-transfer conditions or in the presence of a crown ether. These new reaction conditions are milder and higher yielding than those previously reported. A rationalization for such an unexpected result is put forth and validated by DFT-B3LYP calculations. The results suggest cyclization via a counterion-free (E)-enolate TS.