Catalytic Diamination of Olefins via N–N Bond Activation

Abstract

CONSPECTUS Vicinal diamines are important structural motifs present in various biologically and chemically significant molecules. Direct diamination of olefins provides an effective approach to this class of compounds. Unlike well-established oxidation processes such as epoxidation, dihydroxylation, and aminohydroxylation, direct diamination of olefins had remained a long-standing challenge and had been less well developed. In this Account, we summarize our recent studies on Pd(0)-and Cu(I)-catalyzed diaminations of olefins using di-tert-butyldiaziridinone and its related analogues as nitrogen sources via N–N bond activation. A wide variety of imidazolidinones, cyclic sulfamides, indolines, imidazolinones, and cyclic guanidines can be obtained from conjugated dienes and terminal olefins. For conjugated dienes, the diamination proceeds regioselectively at the internal double bond with the Pd(0) catalyst. Mechanistic studies show that the diamination likely involves a four-membered Pd(II) species resulting from the insertion of Pd(0) into the N–N bond of di-tert-butyldiaziridinone. Interestingly, the Cu(I)-catalyzed process occurs regioselectively at either the terminal or internal double bond depending on the reaction conditions via two mechanistically distinct pathways. The Cu(I) catalyst cleaves the N–N bond of di-tert-butyldiaziridinone to form a Cu(II) nitrogen radical and a four-membered Cu(III) species, which are likely in rapid equilibrium. The Cu(II) nitrogen radical and the four-membered Cu(III) species lead to the terminal and internal diamination, respectively. Terminal olefins are effectively C–H diaminated at the allylic and homoallylic carbons with Pd(0) as catalyst and di-tert-butyldiaziridinone as nitrogen source, likely involving a diene intermediate generated in situ from the terminal olefin via formation of a π-allyl Pd complex and subsequent β-hydride elimination. When di-tert-butylthiadiaziridine 1,1-dioxide is used as nitrogen source, cyclic sulfamides are installed at the terminal carbons via a dehydrogenative diamination process. When α-methylstyrenes (lacking homoallylic hydrogens) react with Pd(0) and di-tert-butyldiaziridinone, spirocyclic indolines are formed with generation of four C–N bonds and one spiro quaternary carbon via allylic and aromatic C–H amination. With Cu(I) catalysts, various terminal olefins can be effectively diaminated at the double bonds using di-tert-butyldiaziridinone, di-tert-butylthiadiaziridine 1,1-dioxide, and 1,2-di-tert-butyl-3-(cyanimino)-diaziridine as nitrogen sources, giving a variety of imidazolidinones, cyclic sulfamides, and cyclic guanidines in good yields, respectively. In the case of monosubstituted olefins using di-tert-butyldiaziridinone as nitrogen source, the resulting diamination products (imidazolidinones) are readily dehydrogenated under the reaction conditions, leading to the corresponding imidazolinones in good yields. Esters can also be diaminated to form the corresponding hydantoins with di-tert-butyldiaziridinone in the presence of ...

Stereoselective and Regioselective Synthesis of Heterocycles via Copper-Catalyzed Additions of Amine Derivatives and Alcohols to Alkenes

“…Many of the strategies are based on palladium catalysis. 59–61 Our contribution, based on copper-facilitated cyclization/oxidative C–N bond formation, stands out as being one of the more diastereoselective processes. 62,63 We have developed both copper-promoted and copper-catalyzed alkene diamination protocols.…”

Enantioselective 1,2-Difunctionalization of Dienes Enabled by Chiral Palladium Complex-Catalyzed Cascade Arylation/Allylic Alkylation Reaction

“…Apparently, the simultaneous control of both the regio-and stereoselectivity renders the proposed threecomponent reaction much more challenging than similar reactions established already. [8][9][10][11] Since the chiral ligands principally coordinates to all of the palladium species formed in whole reaction process, we believe that the use of chiral ligands will be able to provide solutions to formidable issues associated with selectivities. However, the requirement for the chiral ligands to allow the proposed three-component reaction proceeding smoothly is quite critical: they not only enable the palladium to smoothly undergo the oxidative addition to aryl iodine and the subsequent insertion reaction, but also are able to efficiently control the stereoselectivity of the asymmetric allylic alkylation .…”

“…[8][9][10][11][12] However, among these transformations, highly enantioselective 1,2-difunctionlization reactions of 1,3-dienes, in particular, the protocols for the formation of two carbon-carbon bonds, have rarely been reported. 10,11 Very recently, Sigman and co-workers established a Pd(0)-catalyzed intermolecular 1,2-diarylation reaction of 1,3-dienes with aryldiazonium salts and aryl boronic acids, allowing the installation of two different aryl groups. 12 In the presence of a chiral bicyclo [2.2.2]octadiene ligand, the reaction was able to give a good enantiomeric excess, but a rather low yield ( Figure 2a).…”

Catalytic Asymmetric Diamination of Styrenes

“…4 Catalytic diamination of alkenes has thus remained largely limited to reactions involving intramolecular amination steps, 2c, 6 and enantioselective diamination with palladium, 7 copper 8 and titanium 9 catalysts currently requires at least one of the C-N bonds to be formed in an intramolecular reaction. 10 An alternative approach 11 uses homogeneous iodine based redox catalysis, 12 which represents an attractive concept. 13 In this area, enantioselective catalytic transformations that replace existing stoichiometric intermolecular reactions have so far remained elusive.…”