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Silylium‐Catalyzed Carbon–Carbon Coupling of Alkynylsilanes with (2‐Bromo‐1‐methoxyethyl)arenes: Alternative Approaches
Author(s) -
Rubial Belén,
Ballesteros Alfredo,
González José M.
Publication year - 2018
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201800777
Subject(s) - chemistry , alkyne , catalysis , cationic polymerization , alkoxide , combinatorial chemistry , carbon fibers , medicinal chemistry , organic chemistry , materials science , composite number , composite material
The catalytic activation of alkynylsilanes towards 2‐halo‐1‐alkoxyalkyl arenes gives β‐halo‐substituted alkynes. It involves the chemoselective substitution of an alkoxide by an alkyne in the presence of a neighboring C(sp 3 )–Br bond in a cationic C–C bond‐forming event. Two complementary protocols to accomplish this new transformation are reported. The outcome of a direct approach based on mixing the precursors with a freshly prepared solution of the active catalytic species (TMSNTf 2 ) is compared with an alternative based on smooth release of the required silylium ions upon selective activation of the alkyne by gold(I) (JohnPhosAuNTf 2 ). The two approaches gave satisfactory results to access this otherwise elusive alkynylation process, which furnishes 4‐bromo‐substituted alkynes and tolerates various functional groups.