Highly Enantioselective Intramolecular Cyclopropanation Reactions of N-Allylic-N-methyldiazoacetamides Catalyzed by Chiral Dirhodium(II) Carboxamidates
摘要:
Catalytic diazo decomposition of representative N-allylic-N-methyldiazoacetamides produced the corresponding intramolecular cyclopropanation products in good to excellent yields and with exceptional enantiocontrol. In the simplest case, with N-allyl-N-methyldiazoacetamide, catalysis by dirhodium(II) tetrakis[methyl 2-oxapyrrolidine-5(S)-carboxylate], Rh-2(5(S)-MEPY)(4), achieved the highest yield and enantioselectivity (93% eel. Dirhodium(II) tetrakis[methyl 2-oxo-1-(3-phenylpropanoyl)imidazolidin-4(S)-carboxylate] Rh-2(4S)-MPPIM)(4), was preferred for substituted N-allylic-N-methyldiazoacetamides from which 92-95% ee's were obtained in intramolecular cyclopropanation reactions (88-95% yields), even when the catalyst was employed in only 0.1 mol %, Competition with intramolecular dipolar cycloaddition was minimized with the use of N-methyldiazoacetamides relative to N-tert-butyldiazoacetamides.
Organic-Fluorous Phase Switches: A Fluorous Amine Scavenger for Purification in Solution Phase Parallel Synthesis
作者:Bruno Linclau、Ashvani K. Sing、Dennis P. Curran
DOI:10.1021/jo9823442
日期:1999.4.1
The synthesis of the fluorousamine scavenger [(C(6)F(13)CH(2)CH(2))(3)SiCH(2)CH(2)CH(2)](2)NH and its successful application in the automated solution phase parallel synthesis of a urea library are described. Ureas were made by robotic synthesis from organic amines and excess isocyanates. The amine scavenger reacts with excess isocyanate, and the fluorous tag serves to solubilize the resulting adduct
Phosphine-catalyzed acyl-transfer of heteroaryl ketones for the construction of N-fused heterocycles
作者:Yu Zhang、De-Rui Han、Dan Ye、Hong Lu、Hao Wei
DOI:10.1016/j.cclet.2023.108529
日期:2024.3
An inexpensive phosphine catalyst was used effectively for a transition-metal-free acyl-transfer of N-containing heteroaryl ketones for the rapid synthesis of N-fused heterocycles. The key pre-aromatic spirocyclic intermediate initialized by the single electron transfer (SET) process of Togni's reagent II promoted by the tertiaryphosphine resulted in an intriguing and alternative tactic for the cleavage
一种廉价的膦催化剂可有效地用于含N的杂芳基酮的无过渡金属酰基转移,从而实现快速合成N-稠合杂环。由叔膦促进的 Togni 试剂 II 的单电子转移 (SET) 过程引发的关键前芳香螺环中间体产生了一种有趣的替代 C-C 键断裂策略。通过使用廉价的叔膦作为催化剂,这种含N的杂芳基酮的骨架重组方法可以简化复杂的组装N-稠合杂环,具有广泛的官能团耐受性。
Synthesis and structure–activity relationship of 2-(aminoalkyl)-2,3,3a,8-tetrahydrodibenzo[c,f]isoxazolo[2,3-a]azepine derivatives: a novel series of 5-HT2A/2C receptor antagonists. Part 1
作者:J.Ignacio Andrés、Jesús Alcázar、José M Alonso、Adolfo Dı́az、Javier Fernández、Pilar Gil、Laura Iturrino、Encarna Matesanz、Theo F Meert、Anton Megens、Victor K Sipido
DOI:10.1016/s0960-894x(01)00721-1
日期:2002.1
The synthesis of a series of novel 2-(aminoalkyl)-2,3,3a,8-tetrahydrodibenzo[c,f]isoxazolo[2,3-a]azepine derivatives as well as their 5-HT2A/2C and H-1 receptor binding affinities are described. The in vivo activity as potential anxiolytics of the svnthesised compounds was measured in a mCPP challenge test. One of the compounds, 2a, proved to be a potent 5-HT2A 2C c receptor antagonist showing as well oral activity and therefore could be considered as a potential anxiolytic/antidepressant agent. (C) 2002 Elsevier Science Ltd. All rights reserved.
SUBSTITUTED TETRACYCLIC AZEPINE DERIVATIVES WHICH HAVE AFFINITY FOR 5-HT2 RECEPTORS