Alkynylmercury chloride or acetate as intermediates in the mercury(II) salt-promoted addition of aliphatic and aromatic amines to terminal acetylenes

Similarities and Differences between the “Relativistic” Triad Gold, Platinum, and Mercury in Catalysis

“…However, it is interesting to see the similarity between 112 and the intermediate 115, proposed years before for the Hg-catalyzed hydroamination (Scheme 22). [52] No inner-sphere amine attack can occur in the case of Hg II and thus a first sactivated intermediate 116 is proposed and confirmed by reactivity experiments.…”

“…[51,52,104] HgCl 2 , in catalytic amounts, allows the addition of aromatic amines to terminal and internal alkynes in good yields (Scheme 20, condition A). [51,104] When Hg-(OAc) 2 was used, no catalysis was observed because Hg remains bound to the alkene (aminomercuration) and only after NaBH 4 reduction are the corresponding imines/enamines obtained.…”

“…Alkyl amines only react in aminomercuriation processes. [52] Pt II has been also used as catalyst for the addition of aniline (108, R 3 = Ph) to alkynes, although yields were low (Scheme 20, condition B). [48] In contrast, Au I complexes are highly active and, moreover, they can be recovered and recycled (Scheme 20, conditions C and D).…”

Catalytic Hydroamination of Unsaturated Carbon‐Carbon Bonds

“…The hydroamination of alkynes with primary and secondary aliphatic amines necessitates the use of higher amounts of catalyst (17%) and higher temperatures, and TOFs are low (<1 h -1 ) [260]. With aliphatic and aromatic terminal alkynes and a 5-fold excess of primary aliphatic amines, the products are the corresponding imines (40-78% yield, TOF up to 0.3 h -1 ).…”

“…In contrast to the Cu 2 Cl 2 -catalyzed reaction of phenylacetylene and secondary aliphatic amines (Scheme 4-12), the HgCl 2 -catalyzed reaction is fully regioselective for the Markovnikov hydroamination products which do not evolve under the reaction conditions (Eq. 4.66) [260].…”