Rhodium‐ and Palladium‐Catalyzed Hydroarylation of Propargylic Amines with Arylboronic Acids

Abstract

The hydroarylation of 3-arylprop-2-yn-1-amine derivatives with arylboronic acids has been studied in the presence of rhodium or palladium catalysts. By using a rhodium-based catalytic system, b,g-diarylallylamines were isolated in good yields. By contrast, the formation of the regiosomeric g,g-diar-A C H T U N G T R E N N U N G ylallylamines was achieved by means of a palladium catalyst in the presence of acetic acid. The complementary regioselectivity displayed by these two processes is a consequence of different catalytic cycles, involving respectively carborhodation or hydropalladation of the coordinated alkyne as key steps. Calculated charge distributions in the p-complexes are in accord with the results obtained.

Palladium-catalyzed regio- and stereoselective synthesis of aryl and 3-indolyl-substituted 4-methylene-3,4-dihydroisoquinolin-1(2H)-ones

“…The starting N-propargyl-2-iodobenzamides 2 were easily obtained by the reaction of the readily available [41] propargylamines 1 with 2-iodobenzoyl chloride in CH 2 Cl 2 at room temperature (Scheme 2). a Reactions were carried out on a 0.19 mmol scale, using 3 equiv of base, 0.10 equiv of ligand and 0.05 equiv of the palladium catalyst in 2.0 mL of solvent under nitrogen atmosphere.…”

“…The reaction products were purified by flash chromatography on silica gel by elution with n-hexane/EtOAc mixtures. Compounds 1a [44], 1b,c [41], 1d [45], 1e [46] and 5a-c [47] are known products and were identified by comparison of their physical and spectral data obtained with those reported in the cited references. General procedure for the preparation of indole-substituted dihydroisoquinolin-1(2H)-ones 6: To a stirred solution of propargylamide 2 (0.1 mmol) in MeCN (2 mL) were added 2-alkynyltrifluoroacetylanilide 5 (0.12 mmol) and K 2 CO 3 (0.3 mmol); after 5 min stirring at room temperature Pd(PPh 3 ) 4 (0.005 mmol) was added.…”

Palladium-Catalyzed Regio- and Stereoselective Synthesis of Aryl and 3-Indolyl Substituted-4-Methylene- isoquinolin-1(2H)-ones.

“…The starting propargylic 2-iodobenzamides 1 were easily obtained by the reaction of the readily available [20] propargylic amines 1 with 2-iodobenzoyl chloride in CH2Cl2 at room temperature (Scheme 2). Scheme 2.…”

Nickel-catalyzed cyclization of alkyne-nitriles with organoboronic acids involving anti-carbometalation of alkynes

“…The origin of the regioselectivity in this reaction is not clear yet; it is possibly controlled by electronic factors in π–complex 12 (see Scheme 3 ). 11 To understand the role of the OTBS group, alkyne-nitrile 6 without the OTBS group was synthesized. The Ni-catalyzed reaction of 6 with PhB(OH) 2 afforded only 10% of the desired naphthylamine 7 , along with small amounts of an unidentified byproduct ( Scheme 2 , eqn (5)).…”