A palladium‐catalyzed highly regioselective and stereoselective direct arylation of allylamine derivatives with a wide range of thiophenes and furans has been developed. In the presence of palladium(II) acetate [Pd(OAc)2] catalyst and appropriate oxidants, the coupling reaction proceeded with excellent group compatibility and high efficiency, leading exclusively to γ‐arylated linear (E)‐allylamines. It was found that the choice of solvent, olefin substrate and oxidant had an important influence on reaction efficiency, and the use of sterically demanding N,N‐diprotected allylamines bearing a carbamate moiety is crucial for securing high regioselectivity and stereoslectivity. This method provides a straightforward approach for the efficient synthesis of various γ‐heteroarylated, linear (E)‐allylamines.

A general and convenient palladium-catalyzed oxidative Heck arylation of both N-protected and N,N-diprotected allylic amines with arylboronic acids under mild conditions has been developed. The catalyst system, consisting of PdA C H T U N G T R E N N U N G (OAc) 2 (palladium acetate), AgOAc (silver acetate) and KHF 2 (potassium hydrogen fluoride), could efficiently catalyze the coupling reaction in acetone without the aid of any ligand, leading exclusively to the g-arylated allylic amine products in good to excellent yields. This method is highlighted with excellent regio-and stereocontrol and remarkable functional group tolerance. The carbamate moiety in allylic amine substrates is of crucial importance to the catalytic performance, and the chelation between the carbonyl O (oxygen) and Pd (palladium) atoms is believed to be responsible for the high regioselectivity and stereoselectivity observed.

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The combination of Pd(TFA)2 and KOH could efficiently catalyze the reaction of β-substituted allylic halides with arylboronic acids in water.

Thei ridium-catalyzed highly regioselective transfer hydrogenation of av ariety of 2-substituted and2 ,9-disubstituted 1,10-phenanthrolines under mild conditions with formic acid as the hydrogen source is described. In the presence of ac atalytic amount of the iridium complex [Cp*IrCl 2 ] 2 , the transfer hydrogenation proceededs moothly in 1,4-dioxaneu nder ligand-free conditions,e xclusively leading to ar ange of 1,2,3,4-tetrahydro-1,10-phenanthroline productsi nh igh yields.T he catalyst generated in situ from [Cp*IrCl 2 ] 2 and (R,R)-(CF 3 ) 2 C 6 H 3 SO 2 -dpen [N-(2-amino-1,2-diphenylethyl)-3,5-bis(trifluoromethyl)benzenesulfonamide] could efficiently catalyze the asymmetric transfer hydrogenation of these 1,10-phenanthrolinesi ni sopropyl alcohol (i-PrOH)t oa fford chiral 1,2,3,4-tetrahydro-1,10-phenanthrolines in high yields with up to > 99% ee.T he key to the success of the reduction is the choice of solvent and hydrogen source.

An efficient protocol for the direct synthesis of 8-arylated tetrahydroquinolines via Pd-catalyzed ortho-arylation of aryl ureas with aryl iodides was developed. The reaction proceeded smoothly in water under ligand-free and surfactant-free conditions, providing the desired products in high yields with remarkable functional group tolerance.

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ChemCatChem 2014, 6, 311 -318 311 CHEMCATCHEM FULL PAPERS portant structural units in many natural products and pharmaceuticals and serve as versatile starting materials for the synthesis of various functionalized compounds. [14,15] There has been considerable interest in using palladium-catalyzed Mizoroki-Heck arylation of readily accessible allylamines to prepare arylated allylamines, but the regiocontrol remains problematic. [11b, 16, 17] Hallberg, [16a,b] Wu, [16c] Baxter, [11e] and Zhou [11b] reported that the catalyst prepared in situ from a diphosphine ligand and Pd(OAc) 2 could work well to catalyze the coupling reaction of aryl triflates with allylamines to provide the b-arylated products with high regioselectivities and yields; however, the drawbacks associated with the use of aryl triflates, such as base sensitivity and thermal lability, make this method less attractive. Ripin [17d] and Wilson [17e] reported that the palladium-catalyzed highly regioselective and stereoselective terminal arylation of allylamines could be accomplished in alcohol solvents under ligand-free conditions; however, only one aryl iodide substrate was tried. The groups of Sigman, [17h] Cacchi, [17i] and Correia [17j] described Pd 2 (dba) 3 -catalyzed preferential g-arylation of allylamines with arenediazonium salts in the absence of a ligand; however, the synthetic utility of this chemistry could be restricted by the intrinsic drawbacks of arenediazonium salts, such as instability and explosive potential. Despite these advances, it should be pointed out that none of these precedents enable the efficient and selective arylation of allylamines with aryl chlorides.During our investigation of the regioselective arylation of allylamines, [18] we reported that the highly regioselective internal Mizoroki-Heck arylation of N-Boc-allylamine (Boc = tert-butyloxycarbonyl) with aryl bromides could proceed smoothly with palladiumdppp (dppp = 1,3-bis(diphenylphosphino)propane) catalysts in ethylene glycol (EG) and Pd(OAc) 2 could catalyze the coupling reaction of aryl bromides with bulky N,N-diprotected allylamines under ligand-free conditions in water or DMF, preferentially giving the g-arylated products. [18a,b] More recently, we found that the highly regioselective direct arylation of allylamines with thiophenes and furans could be accomplished with Pd(OAc) 2 and suitable additives. [18c] Notably, the electronic and steric properties of allylamine substrates in these reactions have a significant effect on the catalytic activity and regiocontrol. Encouraged by these results and with our continued interest in the regioselective arylation of olefins, herein we report that a palladium catalyst system consisting of Pd(OAc) 2 and appropriate additives efficiently catalyzes the highly regioselective linear (g-)arylation of N,Ndiprotected allylamines with aryl chlorides under ligand-free conditions whereas N-protected allylamines could undergo a highly efficient internal (b-)arylation with aryl chlorides with the Pd-dppf catalyst (dp...