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B. Gröll, P. Schaaf, M. Schnürch:
"Improved simplicity and practicability in copper-catalyzed alkynylation of tetrahydroisoquinoline";
Monatshefte für Chemie, 148 (2017), 91 - 104.

Alkynylation reactions of N-protected tetrahydroisoquinolines
have been performed using several
different protocols of cross dehydrogenative coupling.
Initially, a CuCl-catalyzed method was investigated, which
worked well with three different N-protecting groups,
namely phenyl, PMP, and benzyl and t-BuOOH as oxidant
in acetonitrile as solvent. The peroxide could then be
replaced by simple air and acetonitrile for water, leading to
an overall very environmentally friendly protocol. Finally,
a decarboxylative alkynylation protocol starting from
alkynoic acids was also developed using again air as oxidant.
This avoids the use of gaseous alkynes in the
introduction of short-chained alkyne substituents.

Alkynes; Catalysis; Cross dehydrogenative coupling; Oxidative coupling; Copper catalysis

http://dx.doi.org/10.1007/s00706-016-1877-5

http://publik.tuwien.ac.at/files/publik_264783.pdf