Selective bond formation triggered by short optical pulses: quantum dynamics of a four-center ring closure

2020 ◽  
Vol 22 (39) ◽  
pp. 22302-22313
Author(s):  
Alessio Valentini ◽  
Stephan van den Wildenberg ◽  
F. Remacle
Keyword(s):  
Quantum Dynamics ◽  
Bond Formation ◽  
Ring Closure ◽  
Optical Pulses ◽  
Center Ring

Making bonds with attopulses: quantum dynamics of the ring closure of norbornadiene to quadricyclane.

Oxidative Aromatic C−O Bond Formation: Synthesis of 3-Functionalized Benzo[b]furans by FeCl3-Mediated Ring Closure of α-Aryl Ketones

2009 ◽  
Vol 11 (21) ◽  
pp. 4978-4981 ◽  
Author(s):  
Zhidan Liang ◽  
Weizhe Hou ◽  
Yunfei Du ◽  
Yongliang Zhang ◽  
Yan Pan ◽  
...  
Keyword(s):  
Bond Formation ◽  
Ring Closure ◽  
Aryl Ketones

One-Pot Access to 4-Aryl-2-arylacetoxynaphthalenes via Benz­annulation of Oxygenated Arylacetic Acids and Alkyl Aryl Ketones

Synthesis ◽  
2020 ◽  
Vol 52 (07) ◽  
pp. 1035-1046 ◽  
Author(s):  
Meng-Yang Chang ◽  
Shin-Mei Chen ◽  
Yu-Ting Hsiao
Keyword(s):  
Bond Formation ◽  
Trifluoroacetic Anhydride ◽  
Ring Closure ◽  
One Pot ◽  
Alkyl Aryl ◽  
Highly Effective ◽  
Aryl Ketones ◽  
Arylacetic Acids ◽  
Plausible Mechanism

Trifluoroacetic anhydride mediated one-pot intermolecular formal (4+2) benzannulation of oxygenated arylacetic acids with alkyl aryl ketones provides 4-aryl-2-arylacetoxynaphthalenes in moderate to good yields in the presence of H3PO4 in an open-vessel in a straightforward procedure. A plausible mechanism is proposed and discussed. This protocol provides a highly effective ring-closure via two carbon–carbon (C–C) and one carbon–oxygen (C–O) bond-formation events.

Conjugate addition approach for natural product synthesis inspired by gibberellin and solanoeclepin A targets

2013 ◽  
Vol 85 (6) ◽  
pp. 1149-1160 ◽  
Author(s):  
Minoru Isobe
Keyword(s):  
Oxygen Atom ◽  
Low Temperatures ◽  
Bond Formation ◽  
Conjugate Addition ◽  
Ring Closure ◽  
Natural Product Synthesis ◽  
Partial Synthesis ◽  
Unsaturated Ketones ◽  
Cyclobutane Ring ◽  
Zinc Enolate

Trimethylzincate is known to react through conjugate addition to α,β-unsaturated ketones, but adds much faster to α,β-unsaturated esters at low temperatures. Since the intermediate zinc enolate behaves differently from that of dimethylcuprate, it offers scope for application in a partial synthesis of gibberellin A3. A second example involving vinylsulfones having an oxygen atom on the γ-carbon strongly directs incoming nucleophiles in conjugate addition mode. Heteroatom-directed conjugate addition (HADCA) provides very reactive carbanion intermediates leading to cyclobutane ring formation, necessary for synthesis of solanoeclepin A. An alternative reaction for the four-membered carbocyclic ring closure was explored to make a bond formation between the propargylic cation of Nicholas type and allyltrimethylsilane nucleophile of Hosomi–Sakurai type. This method allowed a formation of tricyclo[5.2.1.01,6]decene framework.

Al/P‐ and Ga/P‐Based Frustrated Lewis Pairs and Electronically Unsaturated Substrates: Ring Cleavage and Ring Closure, C−C and C−N Bond Formation

2019 ◽  
Vol 25 (39) ◽  
pp. 9315-9325 ◽  
Author(s):  
Damian Pleschka ◽  
Marten Uebing ◽  
Merten Lange ◽  
Alexander Hepp ◽  
Anna‐Lena Wübker ◽  
...  
Keyword(s):  
Bond Formation ◽  
Ring Closure ◽  
Ring Cleavage ◽  
Frustrated Lewis Pairs ◽  
Lewis Pairs

ChemInform Abstract: Oxidative Aromatic C-O Bond Formation: Synthesis of 3-Functionalized Benzo[b]furans by FeCl3-Mediated Ring Closure of α-Aryl Ketones.

ChemInform ◽  
2010 ◽  
Vol 41 (12) ◽  
Author(s):  
Zhidan Liang ◽  
Weizhe Hou ◽  
Yunfei Du ◽  
Yongliang Zhang ◽  
Yan Pan ◽  
...  
Keyword(s):  
Bond Formation ◽  
Ring Closure ◽  
Aryl Ketones

Octahedral metal carbonyls. 77. Kinetics of chelate ring closure via olefin-tungsten bond formation in chlorobenzene solvates of tungsten carbonyl intermediates

1992 ◽  
Vol 31 (16) ◽  
pp. 3482-3488 ◽  
Author(s):  
Shulin Zhang ◽  
I Hsiung Wang ◽  
Paul H. Wermer ◽  
Charles B. Dobson ◽  
Gerard R. Dobson
Keyword(s):  
Chelate Ring ◽  
Bond Formation ◽  
Ring Closure ◽  
Metal Carbonyls ◽  
Tungsten Carbonyl ◽  
Kinetics Of

Molecular Iodine-Mediated Synthesis of 2-Azaanthraquinones from [3.3.3]Propellanes via a Metal-Free Rearrangement

Synthesis ◽  
2021 ◽  
Author(s):  
Abdolali Alizadeh ◽  
Akram Bagherinejad ◽  
Mojtaba Khanpour
Keyword(s):  
Ring Opening ◽  
Bond Formation ◽  
Ring Expansion ◽  
Molecular Iodine ◽  
Ring Closure ◽  
Reaction Conditions ◽  
Metal Free ◽  
Green Conditions

AbstractA novel iodine-mediated rearrangement of heterocyclic [3.3.3]propellanes under green conditions is described. This metal-free transformation for the straightforward synthesis of substituted 2-azaanthraquinones proceeds via ring opening/dissociation of C–O and C–N bonds/intramolecular C(sp3)–C(sp3) bond formation/ring expansion/aza-ring closure/1,3-N to N alkyl migration. High atom-efficiency, synthetically useful yields, easily accessible starting materials, and mild reaction conditions are advantages of this process.

scholarly journals Foldamer-templated catalysis of macrocycle formation

Science ◽  
2019 ◽  
Vol 366 (6472) ◽  
pp. 1528-1531 ◽  
Author(s):  
Zebediah C. Girvin ◽  
Mary Katherine Andrews ◽  
Xinyu Liu ◽  
Samuel H. Gellman
Keyword(s):  
Bond Formation ◽  
Three Dimensional ◽  
Human Medicine ◽  
Ring Closure ◽  
Helical Conformation ◽  
Aldol Reactions ◽  
Amino Acid Residues ◽  
Ion Sensing ◽  
Carbon Carbon Bond ◽  
Intermolecular Reactions

Macrocycles, compounds containing a ring of 12 or more atoms, find use in human medicine, fragrances, and biological ion sensing. The efficient preparation of macrocycles is a fundamental challenge in synthetic organic chemistry because the high entropic cost of large-ring closure allows undesired intermolecular reactions to compete. Here, we present a bioinspired strategy for macrocycle formation through carbon–carbon bond formation. The process relies on a catalytic oligomer containing α- and β-amino acid residues to template the ring-closing process. The α/β-peptide foldamer adopts a helical conformation that displays a catalytic primary amine–secondary amine diad in a specific three-dimensional arrangement. This catalyst promotes aldol reactions that form rings containing 14 to 22 atoms. Utility is demonstrated in the synthesis of the natural product robustol.

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