Practical Alkoxythiocarbonyl Auxiliaries for Iridium(I)-Catalyzed C−H Alkylation of Azacycles

Density Functional Theory Calculations for Multiple Conformers Explaining the Regio- and Stereoselectivity of Ti-Catalyzed Hydroaminoalkylation Reactions

Hybrid Density Functional Theory (DFT) calculations for multiple conformers of the insertion reactions of a methylenecyclopropane into the Ti-C bond of two differently α-substituted titanaaziridines explain the experimentally observed differences in regioselectivity between catalytic hydroaminoalkylation reactions of methylenecyclopropanes with α-phenyl-substituted secondary amines and corresponding stoichiometric reactions of a methylenecyclopropane with titanaaziridines, which can only be achieved with α-unsubstituted titanaaziridines. In addition, the lack of reactivity of α-phenyl-substituted titanaaziridines as well as the diastereoselectivity of the catalytic and stoichiometric reactions can be understood.

Regio-, Diastereo-, and Enantioselective Decarboxylative Hydroaminoalkylation of Dienol Ethers Enabled by Dual Palladium/Photoredox Catalysis

Intermolecular photocatalytic hydroaminoalkylation (HAA) of alkenes have emerged as a powerful method for the construction of alkyl amines. Although there are some studies aiming at stereoselective photocatalytic HAA reactions, the alkenes are limited to electrophilic alkenes. Herein, we report a highly regio‐, diastereo‐, and enantioselective HAA of electron‐rich dienol ethers and α‐amino radicals derived from α‐amino acids using a unified photoredox and palladium catalytic system. This decarboxylative 1,2‐Markovnikov addition enables the construction of vicinal amino tertiary ethers with high levels of regio‐ (up to >19 : 1 rr), diastereo‐ (up to >19 : 1 dr), and enantioselectivity control (up to >99 % ee). Mechanistic studies support a reversible hydropalladation as a key step.

Titanium-Catalyzed Hydroaminoalkylation of Ethylene

The first examples of titanium-catalyzed hydroaminoalkylation reactions of ethylene with secondary amines are presented. The reactions can be achieved with various titanium catalysts and they do not require the use of high pressure equipment. In addition, the first solid-state structure of a titanapyrrolidine that is formed by insertion of an alkene into the Ti-C bond of a titanaaziridine is reported.

A General Acid-Mediated Hydroaminomethylation of Unactivated Alkenes and Alkynes

In comparison to the extensively studied metal-catalyzed hydroamination reaction, hydroaminomethylation has received significantly less attention despite its considerable potential to streamline amine synthesis. State-of-the-art protocols for hydroaminomethylation of alkenes rely largely on transition-metal catalysis, enabling this transformation only under highly designed and controlled conditions. Here we report a broadly applicable, acid-mediated approach to the hydroaminomethylation of unactivated alkenes and alkynes. This methodology employs cheap, readily available, and bench-stable reactants and affords the desired amines with excellent functional group tolerance and impeccable regioselectivity. The broad scope of this transformation, as well as mechanistic investigations and in situ domino functionalization reactions are reported.

Enantio- and Diastereoswitchable C-H Arylation of Methylene Groups in Cycloalkanes

A complementary set of chiral N,N-ligands enables the Pd-catalyzed β-C-H arylation of unbiased internal methylene groups in good yield and with high levels of enantio- and diastereoinduction. Both the dia- and enantioselectivity can be reversed, thus allowing the selective arylation of any of the four β-C-H bonds in cycloalkanecarboxamides of various ring sizes. The method is applicable to a broad range of aryl iodides with electron-withdrawing and -donating substituents in the o-, m-, or p-position.

Catalytic and Atom-Economic Csp3 -Csp3 Bond Formation: Alkyl Tantalum Ureates for Hydroaminoalkylation

Atom-economic and regioselective Csp3 -Csp3 bond formation has been achieved by rapid C-H alkylation of unprotected secondary arylamines with unactivated alkenes. The combination of Ta(CH₂ SiMe₃ )₃ Cl₂ , and a ureate N,O-chelating-ligand salt gives catalytic systems prepared in situ that can realize high yields of β-alkylated aniline derivatives from either terminal or internal alkene substrates. These new catalyst systems realize C-H alkylation in as little as one hour and for the first time a 1:1 stoichiometry of alkene and amine substrates results in high yielding syntheses of isolated amine products by simple filtration and concentration.