Recent Advances for the C–C and C–N Bond Formation in the Synthesis­ of 1-Phenethyl-tetrahydroisoquinoline, Aporphine, Homoaporphine­, and β-Carboline Alkaloids

Synthesis ◽  
2017 ◽  
Vol 49 (20) ◽  
pp. 4535-4561 ◽  
Author(s):  
Carlos Puerto Galvis ◽  
Vladimir Kouznetsov
Keyword(s):  
Small Molecules ◽  
Control Strategies ◽  
Bond Formation ◽  
Biological Properties ◽  
Physical Activities ◽  
Organic Transformations ◽  
Reaction Step ◽  
Critical Step ◽  
Metal Catalyzed ◽  
Made In

Among the existing methods for the synthesis of bioactive and/or complex small molecules, organic transformations such as C–C and C–N bond formation have been significantly developed and exploited for the synthesis of diverse synthetic and natural fused aza-polycycles. The abundance and biological and physical activities of 1-phenethyl-tetrahydroisoquinolines, aporphines, homoaporphines, and β-carbolines have inspired many organic chemists to seek sustainable and efficient protocols for their preparation. However, these methodologies involve multiple steps and in most cases the key reaction step is based on the formation of new C–C and/or C–N bonds, and this is usually the critical step that lowers the yields and selectivity. This review is focused on the advances made in recent years regarding the synthesis of these selected natural fused aza-polycycles, overviewing the substrate scope, limitations, regioselectivity, and chemoselectivity, as well as related control strategies of these reactions, concentrating on developments from 2010 to 2016.1 Introduction2 1-Phenethyl-tetrahydroisoquinolines; Dysoxylum Alkaloids3 Aporphines, Homoaporphines, and Semisynthetic Derivatives4 Harmala and Eudistomin Alkaloids and Their Biological Properties5 Metal-Catalyzed C–C Bond Formation6 Pd-Catalyzed C–C and C–N Bond Formation7 Metal-Catalyzed C–N Bond Formation8 [4+2] Cycloaddition in the Synthesis Of Aporphines9 Tandem C–N/C–C Bond Formation: The Pictet–Spengler Reaction10 Miscellaneous Methods11 Conclusions

scholarly journals Photocatalytic Hydrophosphination with Air-Stable and Commercially Available Bis(acetylacetonato)copper(II) (Cu(acac)2)

2020 ◽  
Author(s):  
Steven Dannenberg ◽  
Rory Waterman
Keyword(s):  
Ambient Temperature ◽  
Bond Formation ◽  
Thermal Conditions ◽  
Active Species ◽  
Radical Mechanism ◽  
Water Stability ◽  
Temperature Irradiation ◽  
Highly Effective ◽  
Metal Catalyzed ◽  
Made In

Bis(acetylacetonato)copper(II) (Cu(acac)2, 1), is active for the hydrophosphination of alkenes and alkynes with primary and secondary phosphines. Under thermal conditions, the activity of 1 is comparable to some of the best literature catalysts, but 1 is unique in that set possessing air- and water-stability. However, under ambient temperature irradiation centered at 360 nm, the conversions are remarkable with some reactions complete in minutes and several rarely reported unactivated substrates achieving high conversions within hours. The photocatalytic conditions are critical, and comparison to literature catalysts has been made in which 1 demonstrates superior activity. Initial mechanistic work does not suggest a radical mechanism rather the formation of a copper(I) active species. Hammett analysis indicates that depending on the substrate, either a nucleophilic or insertion-based mechanism may be at work. The enhanced reactivity provided by light also appears to be generalizable to other copper(I) compounds under irradiation, representing a broader phenomenon in metal catalyzed P–C bond formation. This simple, bench-stable, and inexpensive catalyst is highly effective, placing hydrophosphination in the hands of many more synthetic chemists.

Visualizing 3D Molecular Structures Using an Augmented Reality App

2019 ◽  
Author(s):  
Kristina Eriksen ◽  
Bjarne Nielsen ◽  
Michael Pittelkow
Keyword(s):  
Augmented Reality ◽  
Small Molecules ◽  
Computer Modelling ◽  
Simple Procedure ◽  
3D Structure ◽  
Molecular Structures ◽  
Free Software ◽  
Programming Skills ◽  
2D Space ◽  
Made In

<p>We present a simple procedure to make an augmented reality app to visualize any 3D chemical model. The molecular structure may be based on data from crystallographic data or from computer modelling. This guide is made in such a way, that no programming skills are needed and the procedure uses free software and is a way to visualize 3D structures that are normally difficult to comprehend in the 2D space of paper. The process can be applied to make 3D representation of any 2D object, and we envisage the app to be useful when visualizing simple stereochemical problems, when presenting a complex 3D structure on a poster presentation or even in audio-visual presentations. The method works for all molecules including small molecules, supramolecular structures, MOFs and biomacromolecules.</p>

Carbon Dioxide-Mediated C(sp2)–H Arylation of Primary and Secondary Benzylamines

2018 ◽  
Author(s):  
Mohit Kapoor ◽  
Pratibha Chand-Thakuri ◽  
Michael Young
Keyword(s):  
Carbon Dioxide ◽  
Transition Metal ◽  
Bond Activation ◽  
Bond Formation ◽  
Carbon Bond ◽  
Chelate Effect ◽  
Free Amine ◽  
Carbon Carbon Bond ◽  
New Strategy ◽  
Metal Catalyzed

Carbon-carbon bond formation by transition metal-catalyzed C–H activation has become an important strategy to fabricate new bonds in a rapid fashion. Despite the pharmacological importance of <i>ortho</i>-arylbenzylamines, however, effective <i>ortho</i>-C–C bond formation from C–H bond activation of free primary and secondary benzylamines using Pd<sup>II</sup> remains an outstanding challenge. Presented herein is a new strategy for constructing <i>ortho</i>-arylated primary and secondary benzylamines mediated by carbon dioxide (CO<sub>2</sub>). The use of CO<sub>2</sub> is critical to allowing this transformation to proceed under milder conditions than previously reported, and that are necessary to furnish free amine products that can be directly used or elaborated without the need for deprotection. In cases where diarylation is possible, a chelate effect is demonstrated to facilitate selective monoarylation.

scholarly journals Transition Metal-Catalyzed α-Position Carbon–Carbon Bond Formations of Carbonyl Derivatives

Catalysts ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 861 ◽  
Author(s):  
Ha-Eun Lee ◽  
Dopil Kim ◽  
Ahrom You ◽  
Myung Hwan Park ◽  
Min Kim ◽  
...  
Keyword(s):  
Transition Metal ◽  
Carbonyl Compounds ◽  
Bond Formation ◽  
Chiral Ligand ◽  
Catalytic Systems ◽  
Carbon Bond ◽  
Carbonyl Derivatives ◽  
Carbon Carbon Bond ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

α-Functionalization of carbonyl compounds in organic synthesis has traditionally been accomplished via classical enolate chemistry. As α-functionalized carbonyl moieties are ubiquitous in biologically and pharmaceutically valuable molecules, catalytic α-alkylations have been extensively studied, yielding a plethora of practical and efficient methodologies. Moreover, stereoselective carbon–carbon bond formation at the α-position of achiral carbonyl compounds has been achieved by using various transition metal–chiral ligand complexes. This review describes recent advances—in the last 20 years and especially focusing on the last 10 years—in transition metal-catalyzed α-alkylations of carbonyl compounds, such as aldehydes, ketones, imines, esters, and amides and in efficient carbon–carbon bond formations. Active catalytic species and ligand design are discussed, and mechanistic insights are presented. In addition, recently developed photo-redox catalytic systems for α-alkylations are described as a versatile synthetic tool for the synthesis of chiral carbonyl-bearing molecules.

Aryl—Aryl Bond Formation by Transition-Metal-Catalyzed Direct Arylation

ChemInform ◽  
2007 ◽  
Vol 38 (22) ◽  
Author(s):  
Dino Alberico ◽  
Mark E. Scott ◽  
Mark Lautens
Keyword(s):  
Transition Metal ◽  
Bond Formation ◽  
Direct Arylation ◽  
Transition Metal Catalyzed ◽  
Metal Catalyzed

ChemInform Abstract: New Access to H-Phosphonates via Metal-Catalyzed Phosphorus—Oxygen Bond Formation.

ChemInform ◽  
2008 ◽  
Vol 39 (1) ◽  
Author(s):  
Laetitia Coudray ◽  
Isabelle Abrunhosa-Thomas ◽  
Jean-Luc Montchamp
Keyword(s):  
Bond Formation ◽  
Metal Catalyzed ◽  
Oxygen Bond

scholarly journals Protecting group-free, selective cross-coupling of alkyltrifluoroborates with borylated aryl bromides via photoredox/nickel dual catalysis

2015 ◽  
Vol 112 (39) ◽  
pp. 12026-12029 ◽  
Author(s):  
Yohei Yamashita ◽  
John C. Tellis ◽  
Gary A. Molander
Keyword(s):  
Small Molecules ◽  
Functional Group ◽  
Cross Coupling ◽  
Differential Protection ◽  
Coupling Reactions ◽  
Protecting Group ◽  
Cross Coupling Reactions ◽  
Aryl Bromides ◽  
Rapid Construction ◽  
Metal Catalyzed

Orthogonal reactivity modes offer substantial opportunities for rapid construction of complex small molecules. However, most strategies for imparting orthogonality to cross-coupling reactions rely on differential protection of reactive sites, greatly reducing both atom and step economies. Reported here is a strategy for orthogonal cross-coupling wherein a mechanistically distinct activation mode for transmetalation of sp3-hybridized organoboron reagents enables C-C bond formation in the presence of various protected and unprotected sp2-hybridized organoborons. This manifold has the potential for broad application, because orthogonality is inherent to the activation mode itself. The diversification potential of this platform is shown in the rapid elaboration of a trifunctional lynchpin through various transition metal-catalyzed processes without nonproductive deprotection or functional group manipulation steps.

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