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Gold‐Catalyzed Annulations of N ‐Propargyl Ynamides with Anthranils with Two Distinct Chemoselectivities
Author(s) -
Hsu YuChen,
Hsieh ShuAn,
Liu RaiShung
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201806083
Subject(s) - alkyne , propargyl , chemistry , carbene , quinoline , nucleophile , annulation , derivative (finance) , catalysis , methyl vinyl ketone , hydrolysis , ketone , medicinal chemistry , combinatorial chemistry , organic chemistry , financial economics , economics
Abstract Gold‐catalyzed annulation of N ‐propargyl ynamides with anthranils can proceed by two distinct mechanisms. In the case of a terminal N ‐propargyl ynamide, its resulting α‐imino gold carbene reacts with a tethered alkyne to generate a vinyl cation to enable hydrolysis, which ultimately yields a pyrrolo[2,3‐ b ]quinoline derivative after treatment with p ‐toluenesulfonic acid. For an internal alkyne, its α‐imino gold carbene reacts with a tethered alkyne via either a vinyl cation or an alkenylgold carbene; both paths ultimately lead to a 4‐ketone‐2‐aminopyrrole derivative. Our mechanistic analysis indicates that water is a better nucleophile than anthranil for terminal ynamides, whereas water and anthranils are equally reactive for internal ynamides.