α-Functionalization of non-activated aliphatic amines: ruthenium-catalyzed alkynylations and alkylations

Abstract

Novel catalytic alpha-functionalizations of non-activated aliphatic amines with silylated alkynes are reported. In the presence of the Shvo catalyst alkylations and alkynylations proceed highly selectively to the branched amines.

Transition-Metal-Catalyzed Functionalization of C(sp3)&singleBond;H Bonds of Amines

“…Branched a-alkynylated alkylamines are synthesized via metal-catalyzed reaction of nonactivated aliphatic amines and silylacetylenes in the absence of any added oxidizing reagent. [103] The initial idea for the possible reaction sequence is shown in Scheme 45.…”

“…Scheme 45 Ruthenium-Catalyzed Alkynylation of Aliphatic Amines [103] The reaction of tributylamine with (trimethylsilyl)acetylene has been investigated in the temperature range 120-150 8 8C in different solvents and using various metal complexes. [Ir(cod)Cl] 2 , Ir(cod)(acac), Ir(CO) 2 (acac), and RhH(CO)(PPh 3 ) 3 } are not active at all.…”

“…[Ir(cod)Cl] 2 , Ir(cod)(acac), Ir(CO) 2 (acac), and RhH(CO)(PPh 3 ) 3 } are not active at all. [103] The efficiency of the process is improved by the addition of cyclohexanone as a hydrogen acceptor. Addition of 1 equivalent of cyclohexanone increases the yield of the branched propargylamine resulting from reaction of tributylamine with (trimethylsilyl)acetylene to 71% at 1 mol% of catalyst.…”

“…However, when these cyclic amines are applied in the presence of cyclohexanone, the corresponding alkylated products are obtained in addition to, or instead of the alkynylated products 144 (Table 25, entries 9, 10, 12 and 14). [103] for references see p 490…”

Practical Alkoxythiocarbonyl Auxiliaries for Iridium(I)‐Catalyzed C−H Alkylation of Azacycles

“…Direct C–H arylation catalyzed by various transition metal have also been developed [7,8] . In the realm of direct C–H alkylation and related transformations, examples include transition metal-catalyzed C–H activation in the absence (Ta [9] , Ti [10] , Ru [11] catalysts) or presence of directing groups on nitrogen (Ru [12] , Ir [13] and Rh [14] catalysts) had been reported. These strategies generate versatile metal hydride species that can react with either alkenes or a variety of coupling partners such as alkynes and bis(pinacolato)diboron to deliver alkylated, alkenylated and borylated products.…”