Palladium-Catalyzed Vinylation of Aminals with Simple Alkenes: A New Strategy To Construct Allylamines

Catalyst-Free Aminomethylamination of o-Hydroxystyrenes with Aminals to 1,3-Diamines

A new catalyst-free protocol for aminomethylamination of o-hydroxystyrenes with simple aminals is described. This direct and operationally simple method provides a fundamentally novel and rapid approach for the synthesis of 1,3-diamines. This novel reaction occurs under mild reaction conditions and provides a fundamentally unique and efficient strategy for the synthesis of 1,3-diamines with good to excellent yields.

Nickel-Catalyzed Alkylarylation of Activated Alkenes with Benzyl-amines via C-N Bond Activation

A nickel-catalyzed alkylarylation of active alkenes with tertiary benzylamines was achieved by charge-transfer-complex promoted C-N bond activation. The reaction proceeded through initial Ni-catalyzed C-N bond activation, followed by sequential radical addition, redox and proton abstraction with cleaved amine moiety in the absence of oxidant, and provides an efficient method to prepare various alkyl-substituted oxindoles and dihydroquinolinones in good yields.

Recent advances in well-defined, late transition metal complexes that make and/or break C-N, C-O and C-S bonds

Chemical transformations that result in either the formation or cleavage of carbon-heteroatom bonds are among the most important processes in the chemical sciences. Herein, we present a review on the reactivity of well-defined, late-transition metal complexes that result in the making and breaking of C-N, C-O and C-S bonds via fundamental organometallic reactions, i.e. oxidative addition, reductive elimination, insertion and elimination reactions. When appropriate, emphasis is placed on structural and spectroscopic characterization techniques, as well as mechanistic data.

Regioselective 1,2-addition of allenamides with N-haloimides: synthesis of 2-halo allylic aminal derivatives

A strategy for the synthesis of 2-halo allylic aminal derivatives through regioselective 1,2-addition of allenamides with N-haloimides is presented. This reaction was conducted under very mild conditions and gave up to 99% yield. Moreover, the obtained halides allow functional group diversification by palladium-catalyzed coupling reactions, which could act as potential intermediates for the synthesis of valuable compounds.

Featuring Xantphos

This review highlights the use of the bisphosphine ligand group in homogeneous catalysis.

Palladium-Catalyzed Hydroaminocarbonylation of Alkynes with Tertiary Amines via C-N Bond Cleavage

An efficient strategy for the cleavage of the C-N bond of tertiary amines was developed with DTBP as an oxidant, in which the cleaved H atom and amine moiety were successfully transferred to the desired products. This strategy has enabled an efficient palladium-catalyzed hydroaminocarbonylation of alkynes with tertiary amines. Notably, the catalyst loading could be lowered from 5 to 0.1 mol %, which represents the lowest catalyst loading among the reported work on carbonylation via C-N bond activation.

Rh-catalyzed aerobic oxidative cyclization of anilines, alkynes, and CO

We describe a novel Rh-catalyzed C–H cyclization of a wide range of anilines with alkynes and CO. Particularly, simple primary anilines and readily prepared tertiary anilines can be easily converted to quinolin-2(1H)-ones via C–N bond cleavage.

Transition-metal-catalyzed oxidative C–H cyclization of anilines has been an attractive and powerful strategy for the efficient construction of N-heterocycles. However, primary and tertiary anilines are rarely employed in this strategy due to the relative instability with strong oxidants or the presence of three C–N bonds. We describe here a novel Rh-catalyzed C–H cyclization of a wide range of anilines with alkynes and CO, using an aerobic oxidative protocol. Particularly, the simple primary anilines and readily prepared tertiary anilines could be easily converted to quinolin-2(1H)-ones, which are high value-added, biologically significant N-heterocycles, via C–N bond cleavage.

Synthesis of 3-(aminomethyl)pyridine by traceless C3-selective umpolung of 1-amidopyridin-1-ium salts

A natural product inspired rapid access of 3-(aminomethyl)pyridine by one-pot reaction of 1-amidopyridin-1-ium salt with aminal followed by reductive cleavage of the N-N bond is developed. This C3-selective formal C-H activation of pyridine features a traceless umpolung of the 1-amidopyridin-1-ium salt toward a Mannich type C-C bond formation of the in situ generated 1-amido-2-dialkylamino-1,2-dihydropyridine intermediate.

Gold-catalyzed sequential annulations towards 3,4-fused bi/tri-cyclic furans involving a [3+2+2]-cycloaddition

A gold-catalyzed [3+2+2]-cycloaddition towards polysubstituted furan compounds has been realized.

Pd/Cu-Catalyzed aerobic oxidative aromatic C–H bond activation/N-dealkylative carbonylation towards the synthesis of phenanthridinones

A straightforward Pd/Cu-catalyzed oxidative C–H bond activation/N-dealkylative carbonylation of tertiary [1,1′-biphenyl]-2-anilines towards the synthesis of various biologically important phenanthridin-6(5H)-ones has been developed. A wide range of functional groups are well tolerated in this transformation.

Palladium-Catalyzed Oxidative N-Dealkylation/Carbonylation of Tertiary Amines with Alkynes to α,β-Alkynylamides

The first highly effective Pd/C-catalyzed oxidative N-dealkylation/carbonylation of various aliphatic as well as cyclic tertiary amines with alkynes has been described. The selective sp(3) C-N bond activation of tertiary amines at the less steric side using O2 as a sole oxidant and a plausible reaction pathway for the reaction are discussed. The general and operationally simple methodology provides an alternative for the synthesis of a wide range of alk-2-ynamide derivatives under mild conditions. The present protocol is ecofriendly and practical, and it shows significant recyclability.

An Efficient Amide-Aldehyde-Alkene Condensation: Synthesis for the N-Allyl Amides

The allylamine skeleton represents a significant class of biologically active nitrogen compounds that are found in various natural products and drugs with well-recognized pharmacological properties. In this personal account, we will briefly discuss the synthesis of allylamine skeletons. We will focus on showing a general protocol for Lewis acid-catalyzed N-allylation of electron-poor N-heterocyclic amides and sulfonamide via an amide-aldehyde-alkene condensation reaction. The substrate scope with respect to N-heterocyclic amides, aldehydes, and alkenes will be discussed. This method is also capable of preparing the Naftifine motif from N-methyl-1-naphthamide or methyl (naphthalene-1-ylmethyl)carbamate, with paraformaldehyde and styrene in a one-pot manner.

Synthetic methods for 1,3-diamines

In this review, the synthetic methods for the preparation of 1,3-diamines and their applications in synthetic organic chemistry are summarized.

Silver-catalyzed nucleophilic substitution of aminals with ethyl diazoacetate: a new pathway to β-amino-α-diazoesters

A novel silver-catalyzed nucleophilic substitution of aminals with ethyl diazoacetate producing β-amino-α-diazoesters has been developed. A series of aminals with different amino moieties and substituents were successfully incorporated in this reaction.

Base-induced synthesis of N-dialkylaminomethyl-2H-1,2,3-triazoles from N-sulfonyl-1,2,3-triazoles

A facile synthetic method to access N-dialkylaminomethyl-2H-1,2,3-triazoles has been developed from N-sulfonyl-1,2,3-triazoles by a base induced reaction. Moreover, 4-phenyl-1H-1,2,3-triazoles can also give the same product even in the absence of a base at high temperature.

Transition-metal catalysed C–N bond activation

Efficient strategies for transition-metal catalyzed C–N bond activation and their applications in new C–X bond formation reactions are summarized.

Palladium-catalysed coupling reaction of aminals with N-sulfonyl hydrazones to give allylic sulfones

Palladium-catalysed cross-coupling of aminals with N-sulfonyl hydrazones has been established via C–N bond activation under base-free conditions.

C8–H bond activation vs. C2–H bond activation: from naphthyl amines to lactams

Pd-catalyzed selective amine-oriented C8–H bond functionalization/N-dealkylative carbonylation of naphthyl amines has been achieved. The amine group from dealkylation is proposed to be the directing group for promoting this process. It represents a straightforward and easy method to access various biologically important benzo[cd]indol-2(1H)-one derivatives.

Pentacoordinated carboxylate π-allyl nickel complexes as key intermediates for the Ni-catalyzed direct amination of allylic alcohols

Direct amination of allylic alcohols with primary and secondary amines catalyzed by a system made of [Ni(1,5-cyclooctadiene)2 ] and 1,1'-bis(diphenylphosphino)ferrocene was effectively enhanced by adding nBu4 NOAc and molecular sieves, affording the corresponding allyl amines in high yield with high monoallylation selectivity for primary amines and high regioselectivity for monosubstituted allylic alcohols. Such remarkable additive effects of nBu4 NOAc were elucidated by isolating and characterizing some nickel complexes, manifesting the key role of a charge neutral pentacoordinated η(3) -allyl acetate complex in the present system, in contrast to usual cationic tetracoordinated complexes earlier reported in allylic substitution reactions.

Palladium-catalyzed hydroaminocarbonylation of alkenes with amines: a strategy to overcome the basicity barrier imparted by aliphatic amines

A novel and efficient palladium-catalyzed hydroaminocarbonylation of alkenes with aminals has been developed under mild reaction conditions, and allows the synthesis of a wide range of N-alkyl linear amides in good yields with high regioselectivity. On the basis of this method, a cooperative catalytic system operating by the synergistic combination of palladium, paraformaldehyde, and acid was established for promoting the hydroaminocarbonylation of alkenes with both aromatic and aliphatic amines, which do not react well under conventional palladium-catalyzed hydroaminocarbonylation.