A copper-catalyzed carboarylation-ring closure strategy was used for the modular synthesis of oxazolines the reaction of 1-aryl-propargylamides and diaryliodonium salts. The novel approach enables the efficient, modular synthesis of oxazolines derivatives bearing fully substituted exo double bonds.Transition metal-catalyzed ring closures of alkyne derivatives are powerful tools for the construction of heterocyclic molecules.1 With the utilization of hypervalent iodonium salts, 2 the cyclization step can be extended with an additional C-C bond formation using an in situ electrophilic aryl-copper(III) species.3 In our laboratory, we developed an arylation-ring closure strategy enables for the formation of new carbacyclic and heterocyclic molecules via endo-dig cyclization, providing easy access to fully substituted exo double bonds. With the exploitation of the synthetic opportunities of this catalytic approach we synthesized novel benzoxazine derivatives from ortho-ethynylanilides 4 and ortho-acetamidobenzonitriles 5 (Scheme 1). The utilization of diaryliodonium salts in this transformation ensures the high modularity of the methodology.In continuation of our research devoted to the study of copper catalyzed cyclization-arylations with hypervalent reagents, we aimed to extend our synthetic strategy to the construction of five-membered heterocycles such as oxazolines equipped with fully substituted exo double bonds. To achieve this goal we aimed to use propargylic amides as substrates (Scheme 1). The electrophile mediated or transition metal catalyzed cyclizations of propargylic amides to the corresponding oxazolines and oxazoles are important synthetic tools for the access of a heterocyclic core 6 with significant pharmaceutical interest. Although, the existing catalytic transformations enable the cyclization of both terminal and internal propargylic amides, 6 there is no synthetic methodology to the access of oxazolines equipped with fully substituted exo double bonds. Scheme 1. Utilization of arylation-ring closure strategyThe optimization study of the transformation was performed with N-(3-phenylprop-2-ynyl)pivalamide (1a). This model substrate was treated with mesityl(phenyl)iodonium triflate (2a) in the presence of transition-metal catalysts in various solvents under argon. We found that the propargyla-

A novel disconnection based on cross-coupling chemistry was designed to access pharmaceutically relevant aryl-aminoethyl ethers. The developed palladium-catalyzed functionalization of aryl- and heteroaryl chlorides with a sodium tetrakis-(2-chloroethoxy) borate salt is orthogonal to the simple nucleophilic replacement of the chloro function of the ethylene linker. The transformation enables efficient 2-chloroethoxylation in the absence of an additional external base. Subsequent amine substitution of the alkyl halide affords 2-aminoethoxy arenes. The applicability of this method was demonstrated through the synthesis of various aryl- and heteroaryl-alkyl ethers, including the intermediates of marketed drug molecules.

1‐Aryl and 1‐alkylpropargylamides are transformed with arylmesityliodonium salts to deliver oxazoline derivatives with a fully substituted exo double bond in moderate to high yields.