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。
A novel synthetic route to 7-substituted derivatives of the antitumor agent LY231514 (MTA)
作者:Edward C. Taylor、Bin Liu
DOI:10.1016/s0040-4039(99)00959-4
日期:1999.7
This paper describes a further synthesis of the pyrrolo[2,3-d]pyrimidine antitumor agent MTA (LY231514). Manganic triacetate dihydrate-induced radical cyclization of methyl N-crotyl-N-(3',4'-dimethoxybenzyl)malonamide (4d) yielded the 3-carbomethoxy-2-pyrrolidinone 5d that was then thiated with P2S5 to the corresponding thiolactam (6d). Cyclization with guanidine gave the 7-substituted 2-amino-4(3H)-oxo5,6-dihydro-pyrrolo[2,3-d]pyrimidine (7d). Pd-catalyzed coupling with diethyl 4-iodobenzoylglutamate yielded (in a single step) the diethyl ester 9d. Deprotection with H2SO4/TFA followed by saponification then gave MTA. Several additional 7-substituted derivatives of MTA were prepared by use of this methodology. In contradiction to a published claim, these 7-substituted derivatives proved to be devoid of any significant cell growth inhibitory activity. (C) 1999 Elsevier Science Ltd. All rights reserved.