A stereoselective organic base-catalyzed protocol for hydroamination of alkynes under solvent-free conditions

Waste-Minimized Cyanosilylation of Carbonyls Using Fluoride on Polymeric Ionic Tags in Batch and under Continuous Flow Conditions

“…The 3,3-bis­(1 H -imidazol-1-yl)­propan-1-ol ligand was prepared, as previously described, by reduction in the presence of LiAlH 4 of the corresponding methyl ester obtained by the hydroamination reaction between 1 H -imidazole and methyl propiolate . The substitution reaction of chloromethyl-functionalized resins with the ligand 3,3-bis­(1 H -imidazol-1-yl)­propan-1-ol, followed by a quaternization reaction in the presence of iodomethane gave the desired polymer-supported bis-imidazolium organocatalyst POLITAG-I (see Supporting Information for further details, Scheme ).…”

“…The 3,3-bis(1H-imidazol-1-yl)propan-1-ol ligand was prepared, as previously described, by reduction in the presence of LiAlH 4 of the corresponding methyl ester obtained by the hydroamination reaction between 1H-imidazole and methyl propiolate. 79 The substitution reaction of chloromethyl-functionalized resins with the ligand 3,3-bis(1H-imidazol-1yl)propan-1-ol, followed by a quaternization reaction in the presence of iodomethane gave the desired polymer-supported bis-imidazolium organocatalyst POLITAG-I (see Supporting Information for further details, Scheme 1). The efficiency of these post-polymerization functionalization steps has been confirmed by 13 C cross-polarization/magic-angle spinning The corresponding fluorinated materials, POLITAGs-F, have been efficiently obtained by ionic exchange with aqueous KF (Scheme 1) until no silver iodide precipitation could be observed from the eluted solution (see Supporting Information for details).…”

Nickel-Catalyzed Regioselective Hydroamination of Ynamides with Secondary Amines

“…In the past few decades, numerous precious metals, lanthanides, and alkaline earth metals have been widely used to catalyze hydroamination of alkynes . Moreover, base-mediated hydroamination reactions have also been reported in recent years . However, the application of cheap metal Lewis acid remains to be explored for the catalysis of the hydroamination process.…”

Imidazole-Selective Alkyne Hydroamination under Physiological Conditions

“…Base-mediated alkyne hydroamination has been also developed in parallel as a complementary alternative. Various inorganic and organic bases have been shown to promote this valuable C–N bond-forming process. , Nonetheless, intermolecular hydroamination of unactivated alkyne proceeding under mild reaction conditions remains essentially unexplored and even more so for unsymmetrically substituted internal alkynes with potential regiochemistry and ( E / Z )-stereochemistry issues.…”

“…Incidentally, alkyne 1a was found to give hydroamination product 3ba in excellent yield and with perfect regioselectivity and stereoselectivity, when treated with 2-fold excess of TBSCl and imidazole for the protection of the alcohol as TBS ether (Scheme a). It was an unexpected and notably surprising result, as the reaction was not aided by a metal catalyst or base and/or elevated reaction temperature (Scheme b). , …”