Adducts of the Lewis acid [B(C6F5)3] with transition metal oxo compounds

1999 ◽  
pp. 1061-1066 ◽  
Author(s):  
Georgina Barrado ◽  
Linda Doerrer ◽  
Malcolm L. H. Green ◽  
Michael A. Leech
Keyword(s):  
Transition Metal ◽  
Lewis Acid ◽  
Oxo Compounds

Solid-state 17O NMR and computational studies of terminal transition metal oxo compounds

2012 ◽  
Vol 3 (2) ◽  
pp. 391-397 ◽  
Author(s):  
Jianfeng Zhu ◽  
Takuya Kurahashi ◽  
Hiroshi Fujii ◽  
Gang Wu
Keyword(s):  
Solid State ◽  
Transition Metal ◽  
Computational Studies ◽  
17O Nmr ◽  
Oxo Compounds

Development of silica-supported frustrated Lewis pairs: highly active transition metal-free catalysts for the Z-selective reduction of alkynes

2016 ◽  
Vol 6 (3) ◽  
pp. 882-889 ◽  
Author(s):  
Kai C. Szeto ◽  
Wissam Sahyoun ◽  
Nicolas Merle ◽  
Jessica Llop Castelbou ◽  
Nicolas Popoff ◽  
...  
Keyword(s):  
Transition Metal ◽  
Lewis Acid ◽  
Selective Reduction ◽  
Frustrated Lewis Pairs ◽  
Acid Base ◽  
Metal Free ◽  
Highly Active ◽  
Active Transition ◽  
Lewis Pairs

Supported Lewis acid/base systems based have been prepared and characterized.

Metathetical Degradation and Depolymerization of Unsaturated Polymers

1997 ◽  
Vol 70 (3) ◽  
pp. 519-529 ◽  
Author(s):  
J. C. Marmo ◽  
K. B. Wagener
Keyword(s):  
Molecular Weight ◽  
Transition Metal ◽  
Catalytic System ◽  
Lewis Acid ◽  
Catalyst System ◽  
Metal Catalysts ◽  
Transition Metal Catalysts ◽  
Side Reactions

Abstract The employment of transition metal catalysts has been a viable route in the degradation and depolymerization of unsaturated polymers. Initially, unsaturated polymers were degraded with a catalytic system containing a transition metal and a Lewis acid cocatalyst (WCl6/SnBu4). Degradation chemistry was effective in reducing the molecular weight of the polymer, however, the classical catalyst system induces side reactions which generates ill-defined products. These side reactions were obviated by using a preformed alkylidene without a Lewis acid cocatalyst, and perfectly difunctional telechelics were synthesized.

scholarly journals Recent Developments in Polyene Cyclizations and Their Applications in Natural Product Synthesis

Synthesis ◽  
2018 ◽  
Vol 51 (01) ◽  
pp. 67-82 ◽  
Author(s):  
Anthony Barrett ◽  
Tsz-Kan Ma ◽  
Thomas Mies
Keyword(s):  
Transition Metal ◽  
Natural Product ◽  
Lewis Acid ◽  
Multiple Bond ◽  
Natural Product Synthesis ◽  
Cyclization Reactions ◽  
Cascade Cyclizations ◽  
Highly Efficient ◽  
Recent Developments ◽  
Radical Cascade

Cascade polyene cyclization reactions are highly efficient and elegant bioinspired transformations that involve simultaneous multiple bond constructions to rapidly generate complex polycyclic molecules. This review summarizes the most prominent work on a variety of cationic and radical cascade cyclizations and their applications in natural product synthesis published between 2014 and 2018.1 Introduction2 Cationic Polyene Cyclizations2.1 Lewis Acid Mediated Polyene Cyclizations2.2 Brønsted Acid Mediated Polyene Cyclizations2.3 Halogen Electrophile Initiated Polyene Cyclizations2.4 Sulfur Electrophile Initiated Polyene Cyclizations2.5 Transition-Metal-Mediated Cationic Polyene Cyclizations3 Radical Polyene Cyclizations3.1 Transition-Metal-Mediated Radical Polyene Cyclizations3.2 Photocatalyst-Mediated Polyene Cyclizations4 Origin of Stereocontrol in Polyene Cyclizations5 Conclusion

Novel Naproxen Derivatives: Lewis Acid/Transition-metal Free Synthesis via C-C Bond Forming Reaction

2007 ◽  
Vol 4 (4) ◽  
pp. 292-295 ◽  
Author(s):  
Sarbani Pal ◽  
P. Bindu ◽  
Pragnyadhar Reddy Venna ◽  
P. K. Dubey
Keyword(s):  
Transition Metal ◽  
Lewis Acid ◽  
Metal Free ◽  
Bond Forming

Merging gold catalysis, organocatalytic oxidation, and Lewis acid catalysis for chemodivergent synthesis of functionalized oxazoles from N-propargylamides

2017 ◽  
Vol 53 (75) ◽  
pp. 10366-10369 ◽  
Author(s):  
Shaoyu Mai ◽  
Changqing Rao ◽  
Ming Chen ◽  
Jihu Su ◽  
Jiangfeng Du ◽  
...  
Keyword(s):  
Transition Metal ◽  
Lewis Acid ◽  
Lewis Acids ◽  
Acid Catalysis ◽  
Gold Catalysis ◽  
One Pot ◽  
Catalytic Systems ◽  
One Pot Synthesis ◽  
The One ◽  
Cationic Gold

Novel catalytic systems consisting of cationic gold complexes, N-hydroxyphthalimide (NHPI), and transition-metal-based Lewis acids have been developed for the one-pot synthesis of functionalized oxazoles.

Hafnium Triflate as a Highly Potent Catalyst for Regio- and Chemoselective­ Deprotection of Silyl Ethers

Synthesis ◽  
2018 ◽  
Vol 51 (04) ◽  
pp. 944-952 ◽  
Author(s):  
Shan-Shan Gong ◽  
Qi Sun ◽  
Xiu-An Zheng ◽  
Rui Kong ◽  
Hua-Shan Huang ◽  
...  
Keyword(s):  
Transition Metal ◽  
Lewis Acid ◽  
Protecting Groups ◽  
High Potency ◽  
Silyl Ethers

As a Group IVB transition metal Lewis acid, hafnium triflate [Hf(OTf)4] exhibited exceptionally high potency in desilylations. Since the amounts of Hf(OTf)4 required for the deprotection of 1°, 2°, 3° alkyl and aryl tert-butyldimethylsilyl (TBS) ethers are significantly different, ranging from 0.05 mol% to 3 mol%, regioselective deprotection of TBS could be easily implemented. Moreover, chemoselective cleavage of different silyl ethers or removal of TBS in the presence of most hydroxyl protecting groups was also accomplished. NMR analyses of silyl products from TBS deprotection indicated that Hf(OTf)4-catalyzed desilylation may proceed via different mechanisms, depending on the solvent used.

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