8.4.5. Nitromercuration Reactions 3878 9. Hydroamination of Alkenes and Alkynes under Microwave Irradiation 3878 * To whom correspondence should be addressed. Phone: +49 241 8

Hydroamination: direct addition of amines to alkenes and alkynes.

The legacy of Gilbert Newton Lewis (1875-1946) pervades the lexicon of chemical bonding and reactivity. The power of his concept of donor-acceptor bonding is evident in the eponymous foundations of electron-pair acceptors (Lewis acids) and donors (Lewis bases). Lewis recognized that acids are not restricted to those substances that contain hydrogen (Bronsted acids), and helped overthrow the "modern cult of the proton". His discovery ushered in the use of Lewis acids as reagents and catalysts for organic reactions. However, in recent years, the recognition that Lewis bases can also serve in this capacity has grown enormously. Most importantly, it has become increasingly apparent that the behavior of Lewis bases as agents for promoting chemical reactions is not merely as an electronic complement of the cognate Lewis acids: in fact Lewis bases are capable of enhancing both the electrophilic and nucleophilic character of molecules to which they are bound. This diversity of behavior leads to a remarkable versatility for the catalysis of reactions by Lewis bases.

Lewis Base Catalysis in Organic Synthesis

Late transition metal-catalyzed hydroamination and hydroamidation.

High oxidation state multiple metal-carbon bonds.

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Chemicals from Alkynes with Palladium Catalysts

The development of a highly active and selective porphyrin-based epoxide carbonylation catalyst, [(OEP)Cr(THF)2][Co(CO)4] (1; OEP = octaethylporphyrinato; THF = tetrahydrofuran), is detailed. Complex 1 is a separated ion pair composed of a tetracarbonylcobaltate anion and an octahedral chromium porphyrin complex axially ligated by two THF ligands. Regarding the carbonylation of epoxides to β-lactones, catalyst 1 exhibits excellent turnover numbers (up to 10 000) and turnover frequencies (up to 1670 h-1), with regioselective carbonyl insertion occurring between the oxygen and the sterically less hindered carbon of the epoxide substrate. Complex 1 is highly tolerant of nonprotic functional groups, carbonylating an array of aliphatic and cycloaliphatic epoxides, as well as epoxides with pendant ethers, esters, and amides. With careful control of reaction conditions in the carbonylation of glycidyl esters, the exclusive production of either the β- or γ-lactone isomer was achieved. Through analysis of reaction...

Chromium(III) octaethylporphyrinato tetracarbonylcobaltate: a highly active, selective, and versatile catalyst for epoxide carbonylation.

A readily synthesized and highly active epoxide carbonylation catalyst based on a chromium porphyrin framework: expanding the range of available beta-lactones.

A series of sterically hindered amidinate ligands containing terphenyl substituents at the carbon atom of the amidinate backbone have been synthesized in high yields; their lithium derivatives were prepared, including the first two examples of monodentate lithium amidinates Additionally, two independent routes to magnesium amidinates have been developed, yielding both mono- and bis-amidinate magnesium complexes The presence of substituents at the 2′, 6′, 2″, and 6″ positions on the terphenyl moieties attached to the amidinate backbone induces a strong steric effect In the free-base amidines, equilibria between E-syn and Z-syn isomers were dependent upon the size of these groups, while in the lithium amidinates, the steric bulk of these ligands led to the formation of the first monodentate lithium amidinates Finally, in the magnesium amidinates, short C–N bond lengths and reduced N–C–N bond angles
were observed within the amidinate backbone

Joseph A. R. Schmidt

Papers

Chromium(III) octaethylporphyrinato tetracarbonylcobaltate: a highly active, selective, and versatile catalyst for epoxide carbonylation.

A readily synthesized and highly active epoxide carbonylation catalyst based on a chromium porphyrin framework: expanding the range of available beta-lactones.

Synthesis and characterization of a series of sterically-hindered amidines and their lithium and magnesium complexes

Mono-amidinate complexes stabilized by a new sterically-hindered amidine†

Neutral and Cationic Aluminum Complexes Supported by Sterically Bulky Amidinate Ligands