skip to main content


Title: Catalytic C(sp 3 )−H Arylation of Free Primary Amines with an exo Directing Group Generated In Situ
Abstract

Herein, we report the palladium‐catalyzed direct arylation of unactivated aliphatic C−H bonds in free primary amines. This method takes advantage of anexo‐imine‐type directing group (DG) that can be generated and removed in situ. A range of unprotected aliphatic amines are suitable substrates, undergoing site‐selective arylation at the γ‐position. Methyl as well as cyclic and acyclic methylene groups can be activated. Furthermore, when aniline‐derived substrates were used, preliminary success with δ‐C−H arylation was achieved. The feasibility of using the DG component in a catalytic fashion was also demonstrated.

 
more » « less
NSF-PAR ID:
10235938
Author(s) / Creator(s):
 ;  ;  ;  ;  
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
Angewandte Chemie
Volume:
128
Issue:
31
ISSN:
0044-8249
Page Range / eLocation ID:
p. 9230-9233
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. Abstract

    Directed C−H functionalization has been realized as a complimentary technique to achieve borylation at a distal position of aliphatic amines. Here, we demonstrated the oxidative borylation at the distal δ‐position of aliphatic amines using various borylating agents, a palladium catalyst, and a rightly tuned ligand in the presence of a cheap oxidant. Moreover, an organopalladium δ‐C(sp3)‐H‐activated intermediate has been isolated and crystallographically characterized to get mechanistic insight.

     
    more » « less
  2. Abstract

    Directed C−H functionalization has been realized as a complimentary technique to achieve borylation at a distal position of aliphatic amines. Here, we demonstrated the oxidative borylation at the distal δ‐position of aliphatic amines using various borylating agents, a palladium catalyst, and a rightly tuned ligand in the presence of a cheap oxidant. Moreover, an organopalladium δ‐C(sp3)‐H‐activated intermediate has been isolated and crystallographically characterized to get mechanistic insight.

     
    more » « less
  3. Abstract

    Three new polynuclear clusters with the formulae [Mn10O4(OH)(OMe){(py)2C(O)2}2{(py)2C(OMe)(O)}4(MeCO2)6](ClO4)2(1), Na[Mn12O2(OH)3(OMe){(py)2C(O)2}6{(py)2C(OH)(O)}2(MeCO2)2(H2O)10](ClO4)8(2) and [Mn12O4(OH)2{(py)2C(O)2}6{(py)2C(OMe)(O)}(MeCO2)3(NO3)3(H2O)(DMF)2](NO3)2(3) were prepared from the combination of di‐2‐pyridyl ketone, (py)2CO, with the aliphatic diols (1,3‐propanediol (pdH2) or 1,4‐butanediol (1,4‐bdH2)) in Mn carboxylate chemistry. The reported compounds do not include the aliphatic diols employed in this reaction scheme; however, their use is essential for the formation of13. The crystal structures of13are based on multilayer cores which, to our knowledge, are reported for the first time in Mn cluster chemistry. Direct current (dc) magnetic susceptibility studies showed the presence of dominant antiferromagnetic exchange interactions within13. Alternating current (ac) magnetic susceptibility studies revealed the presence of out‐of‐phase signals below 3.0 K for2and3indicating the slow relaxation of the magnetization vector, characteristic of single‐molecule magnets; theUeffvalue of2was found to be 23 K and the preexponential factorτ0~7.6×10−9 s.

     
    more » « less
  4. Abstract

    Group I alkoxides are highly active precatalysts in the heterodehydrocoupling of silanes and amines to afford aminosilane products. The broadly soluble and commercially available KOtAmyl was utilized as the benchmark precatalyst for this transformation. Challenging substrates such as anilines were found to readily couple primary, secondary, and tertiary silanes in high conversions (>90 %) after only 2 h at 40 °C. Traditionally challenging silanes such as Ph3SiH were also easily coupled to simple primary and secondary amines under mild conditions, with reactivity that rivals many rare earth and transition‐metal catalysts for this transformation. Preliminary evidence suggests the formation of hypercoordinated intermediates, but radicals were detected under catalytic conditions, indicating a mechanism that is rare for Si−N bond formation.

     
    more » « less
  5. A highly selective palladium-catalyzed carbonylative arylation of weakly acidic benzylic C(sp 3 )–H bonds of azaarylmethylamines with aryl bromides under 1 atm of CO gas has been achieved. This work represents the first examples of use of such weakly acidic pronucleophiles in this class of transformations. In the presence of a NIXANTPHOS-based palladium catalyst, this one-pot cascade process allows a range of azaarylmethylamines containing pyridyl, quinolinyl and pyrimidyl moieties and acyclic and cyclic amines to undergo efficient reactions with aryl bromides and CO to provide α-amino aryl-azaarylmethyl ketones in moderate to high yields with a broad substrate scope and good tolerance of functional groups. This reaction proceeds via in situ reversible deprotonation of the benzylic C–H bonds to give the active carbanions, thereby avoiding prefunctionalized organometallic reagents and generation of additional waste. Importantly, the operational simplicity, scalability and diversity of the products highlight the potential applicability of this protocol. 
    more » « less