Transformation of Open-Chain Thioether-Dithiolato to Cyclic Thioether Ligands by C?S Bond Cleavage and Bond Formation at Ruthenium Centers: Synthesis of the Trithiobenzo[9]crown-3 Complex [Ru(Bzo-9S3)(CO)Br2]

1988 ◽  
Vol 27 (5) ◽  
pp. 691-692 ◽  
Author(s):  
Dieter Sellmann ◽  
Falk Knoch ◽  
Christina Wronna
Keyword(s):  
Bond Cleavage ◽  
Bond Formation ◽  
Open Chain

Radiolysis of methylcyclopentane. III. Liquid phase mechanism and comparison of cycloalkanes

1968 ◽  
Vol 46 (20) ◽  
pp. 3235-3240 ◽  
Author(s):  
Gordon R. Freeman ◽  
E. Diane Stover
Keyword(s):  
Liquid Phase ◽  
Gas Phase ◽  
Bond Cleavage ◽  
Open Chain ◽  
Methyl Substitution ◽  
Product Yields ◽  
Total Ionization ◽  
Gamma Radiolysis ◽  
G Value

The initial yields of the major products of the gamma radiolysis of liquid methylcyclopentane (MCP) at 25° are: G(H2) = 4.2, G(1-methylcyclopentene plus methylenecyclopentane) = 2.7, G(3- plus 4-methyl-cyclopentene) = 1.0, G(open chain hexene) = 1.0, and G(bimethylcyclopentyl) = 0.9. The effects of scavengers on the product yields are reported and the mechanism is discussed.The liquid phase radiolytic decompositions of cyclohexane (CH), methylcyclohexane (MCH), cyclopentane (CP), and MCP are compared. The net amount of C—C bond cleavage is much greater in the five-membered than in the six-membered rings. Methyl substitution on the ring reduces G(H2) by about one unit, mainly because of the formation of a type of ion (QH+) that does not yield hydrogen when neutralized by an electron. The QH+ type ions are formed in MCH and MCP, but not in CH and CP. In all the systems, another type of ion (N+) that does not yield hydrogen when neutralized by an electron is formed with a G value of about unity. The type of ion (PH+) that does yield hydrogen when neutralized by an electron has a G value of 3.4 in CH and CP, but only 2.0 in MCP. It is concluded that G(total ionization) is in the vicinity of 4.4 in the liquid compounds, virtually the same as the gas phase values.

Organozinc-Mediated Direct C−C Bond Formation via C−N Bond Cleavage of Ammonium Salts

2017 ◽  
Vol 12 (19) ◽  
pp. 2554-2557 ◽  
Author(s):  
Dong-Yu Wang ◽  
Koki Morimoto ◽  
Ze-Kun Yang ◽  
Chao Wang ◽  
Masanobu Uchiyama
Keyword(s):  
Bond Cleavage ◽  
Bond Formation ◽  
Ammonium Salts

Double C–H Activation for the C–C bond Formation Reactions

2018 ◽  
Vol 15 (7) ◽  
pp. 882-903 ◽  
Author(s):  
Jialin Liu ◽  
Xiaoyu Xiong ◽  
Jie Chen ◽  
Yuntao Wang ◽  
Ranran Zhu ◽  
...  
Keyword(s):  
Molecular Design ◽  
Bond Cleavage ◽  
Bond Formation ◽  
Hypervalent Iodine ◽  
Coupling Reactions ◽  
Bond Forming ◽  
Direct Functionalization ◽  
Catalyzed Reactions ◽  
Medium Ring ◽  
Bond Formation Reactions

Background: Among the numerous bond-forming patterns, C–C bond formation is one of the most useful tools for building molecules for the chemical industry as well as life sciences. Recently, one of the most challenging topics is the study of the direct coupling reactions via multiple C–H bond cleavage/activation processes. A number of excellent reviews on modern C–H direct functionalization have been reported by Bergman, Bercaw, Yu and others in recent years. Among the large number of available methodologies, Pdcatalyzed reactions and hypervalent iodine reagent mediated reactions represent the most popular metal and non-metal involved transformations. However, the comprehensive summary of the comparison of metal and non-metal mediated transformations is still not available. Objective: The review focuses on comparing these two types of reactions (Pd-catalyzed reactions and hypervalent iodine reagent mediated reactions) based on the ways of forming new C–C bonds, as well as the scope and limitations on the demonstration of their synthetic applications. Conclusion: Comparing the Pd-catalyzed strategies and hypervalent iodine reagent mediated methodologies for the direct C–C bond formation from activation of C-H bonds, we clearly noticed that both strategies are powerful tools for directly obtaining the corresponding pruducts. On one hand, the hypervalent iodine reagents mediated reactions are normally under mild conditions and give the molecular diversity without the presence of transition-metal, while the Pd-catalyzed approaches have a broader scope for the wide synthetic applications. On the other hand, unlike Pd-catalyzed C-C bond formation reactions, the study towards hypervalent iodine reagent mediated methodology mainly focused on the stoichiometric amount of hypervalent iodine reagent, while few catalytic reactions have been reported. Meanwhile, hypervalent iodine strategy has been proved to be more efficient in intramolecular medium-ring construction, while there are less successful examples on C(sp3)–C(sp3) bond formation. In summary, we have demonstrated a number of selected approaches for the formation of a new C–C bond under the utilization of Pd-catalyzed reaction conditions or hyperiodine reagents. The direct activations of sp2 or sp3 hybridized C–H bonds are believed to be important strategies for the future molecular design as well as useful chemical entity synthesis.

Oxidative C–S bond cleavage reaction of DMSO for C–N and C–C bond formation: new Mannich-type reaction for β-amino ketones

RSC Advances ◽  
2015 ◽  
Vol 5 (4) ◽  
pp. 3094-3097 ◽  
Author(s):  
Kai Sun ◽  
Yunhe Lv ◽  
Zhonghong Zhu ◽  
Liping Zhang ◽  
Hankui Wu ◽  
...  
Keyword(s):  
Bond Cleavage ◽  
Bond Formation ◽  
Cleavage Reaction ◽  
Type Reaction ◽  
Bond Cleavage Reaction

A novel oxidative C–S bond cleavage reaction of DMSO for N-methylation and subsequent C–C bond formation is described.

I2/TBHP-Promoted Approach to α-Keto Esters from Trifluoromethyl β-Diketones and Alcohols via C–C Bond Cleavage

Synlett ◽  
2017 ◽  
Vol 28 (15) ◽  
pp. 2018-2023 ◽  
Author(s):  
Xiang Fang ◽  
Xueyan Yang ◽  
Tongle Shao ◽  
Jun Zhou ◽  
Chen Jin ◽  
...  
Keyword(s):  
Oxidative Coupling ◽  
Bond Cleavage ◽  
Bond Formation ◽  
Coupling Reaction ◽  
Mechanistic Studies ◽  
Metal Free ◽  
Oxidation Pathway ◽  
Keto Esters ◽  
Oxidative Coupling Reaction

A metal-free oxidative coupling reaction of trifluoromethyl β-diketones with alcohols for the synthesis of α-keto esters in good to excellent yields has been developed. Preliminary mechanistic studies suggest that an I2/TBHP promoted sequential iodination, C–C bond cleavage, C–O bond formation and oxidation pathway is involved in this reaction.

Iminyl-Radical-Triggered C–C Bond Cleavage of Cycloketone Oxime Derivatives: Generation of Distal Cyano-Substituted Alkyl Radicals and Their Functionalization

Synthesis ◽  
2020 ◽  
Vol 52 (11) ◽  
pp. 1585-1601 ◽  
Author(s):  
Tiebo Xiao ◽  
Lei Zhou ◽  
Hongtai Huang ◽  
Devireddy Anand
Keyword(s):  
Halogen Bond ◽  
Cyano Group ◽  
Bond Cleavage ◽  
Bond Formation ◽  
Radical Reaction ◽  
Building Blocks ◽  
Aromatic Rings ◽  
Organometallic Reagents ◽  
Alkyl Radicals ◽  
Oxime Derivatives

Alkyl nitriles are versatile building blocks in organic synthesis because the cyano group can be easily converted into other functional groups. Iminyl-radical-triggered C–C bond cleavage of cycloketone oxime­ derivatives provides a practical route to access distal cyano-substituted alkyl radicals, which has given chemists a new radical reaction platform for the synthesis of diverse alkyl nitriles. This review provides an overview of various types of radical cyanoalkylation via ring opening of cycloketone oxime derivatives.1 Introduction2 C–C Bond Formation2.1 Alkenes as Radical Acceptors2.2 Aromatic Rings as Radical Acceptors2.3 Organometallic Reagents as Radical Acceptors2.4 Cyanoalkyl-Radical-Triggered Cyclization Reactions2.5 Miscellaneous3 C–Heteroatom Bond Formation3.1 C–O Bond Formation3.2 C–N Bond Formation3.3 C–S Bond Formation3.4 C–Halogen Bond Formation3.5 C–B Bond Formation4 Conclusion

Reductase of Mutanobactin Synthetase Triggers Sequential C–C Macrocyclization, C–S Bond Formation, and C–C Bond Cleavage

2020 ◽  
Vol 22 (3) ◽  
pp. 960-964
Author(s):  
Min Wang ◽  
Zhoujie Xie ◽  
Shoubin Tang ◽  
Ee Ling Chang ◽  
Yue Tang ◽  
...  
Keyword(s):  
Bond Cleavage ◽  
Bond Formation

Carbon–Carbon Bond Formation of Trifluoroacetyl Amides with Grignard Reagents via C(O)–CF3 Bond Cleavage

2019 ◽  
Vol 84 (9) ◽  
pp. 5635-5644 ◽  
Author(s):  
Longzhi Zhu ◽  
Liyuan Le ◽  
Mingpan Yan ◽  
Chak-Tong Au ◽  
Renhua Qiu ◽  
...  
Keyword(s):  
Bond Cleavage ◽  
Bond Formation ◽  
Grignard Reagents ◽  
Carbon Bond ◽  
Carbon Carbon Bond
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