TY - JOUR T1 - Mechanistic Insights into Rhenium-Catalyzed Regioselective C-Alkenylation of Phenols with Internal Alkynes. AU - Murai,Masahito, AU - Yamamoto,Masaki, AU - Takai,Kazuhiko, Y1 - 2019/10/30/ PY - 2019/08/27/received PY - 2019/09/17/revised PY - 2019/9/19/pubmed PY - 2019/9/19/medline PY - 2019/9/19/entrez KW - alkenylation KW - homogeneous catalysis KW - reaction mechanisms KW - regioselectivity KW - rhenium SP - 15189 EP - 15197 JF - Chemistry (Weinheim an der Bergstrasse, Germany) JO - Chemistry VL - 25 IS - 66 N2 - A (μ-aryloxo)rhenium complex was isolated and confirmed as a key precatalyst for rhenium-catalyzed ortho-alkenylation (C-alkenylation) of unprotected phenols with alkynes. The reaction exclusively provided ortho-alkenylphenols; the formation of para or multiply alkenylated phenols and hydrophenoxylation (O-alkenylation) products was not observed. Several mechanistic experiments excluded a classical Friedel-Crafts-type mechanism, leading to the proposed phenolic hydroxyl group assisted electrophilic alkenylation as the most plausible reaction mechanism. For this purpose, the use of rhenium, a metal between the early and late transition metals in the periodic table, was key for the activation of both the soft carbon-carbon triple bond of the alkyne and the hard oxygen atom of the phenol, at the same time. ortho-Selective alkenylation with allenes also provided the corresponding adducts with a substitution pattern different from that obtained by the addition reaction with alkynes. SN - 1521-3765 UR - https://www.unboundmedicine.com/medline/citation/31532028/Mechanistic_Insights_into_Rhenium_Catalyzed_Regioselective_C_Alkenylation_of_Phenols_with_Internal_Alkynes_ DB - PRIME DP - Unbound Medicine ER -