Synthesis of 1,3‐Diamines Through Rhodium‐Catalyzed CH Insertion

Abstract

A grand opening: N-Boc-N-alkylsulfamides are effective substrates for the title transformation. Oxidative cyclization is highly chemoselective as well as being both stereospecific and diastereoselective. With the advent of new protocols that facilitate ring opening of the six-membered-ring heterocyclic products, access to differentially protected 1,3-diamines has been made possible (see scheme).

Complementary Strategies for Directed C(sp3)−H Functionalization: A Comparison of Transition‐Metal‐Catalyzed Activation, Hydrogen Atom Transfer, and Carbene/Nitrene Transfer

“…The opposite diastereomer can be obtained when sulfamide 507 is employed as the substrate. [203] In this case,the methyl group is placed in the pseudoaxial position to minimize A 1,3 strain with the NBoc group in transition state K2.…”

Komplementäre Strategien für die dirigierte C(sp3)‐H‐Funktionalisierung: ein Vergleich von übergangsmetallkatalysierter Aktivierung, Wasserstoffatomtransfer und Carben‐ oder Nitrentransfer

“…Das entgegengesetzte Diastereomer kann erhalten werden, wenn das Sulfamid 507 als Substrat eingesetzt wird. [202] In diesem Fall ist die Methylgruppe in pseudoaxialer Position angeordnet, was dazu führt, dass die A 1,3 -Spannung zwischen dieser und der NBocGruppe im Übergangszustand K2 verringert ist.…”

Stereoselective Radical Amination of Electron-Deficient C(sp3)–H Bonds by Co(II)-Based Metalloradical Catalysis: Direct Synthesis of α-Amino Acid Derivatives via α-C–H Amination

“…3 To the best of our knowledge, the only previous report that briefly touched the subject is the Rh 2 -catalyzed intramolecular α-C–H amination of N -Boc-protected sulfamide esters. 4,5 Evidently, amination of electron-deficient C–H bonds is an unaddressed issue that faces formidable challenges in both reactivity and regioselectivity.…”

“…Higher to excellent diastereoselectivities were achieved for regioselective α-C–H amination of enantiopure γ-substituted azide esters 1g–1h , affording optically active bis-α-amino acid derivatives 2g–2h in high yields (entries 7–8), which is in stark contrast to the Rh 2 -catalyzed amination. 4 Furthermore, β,γ-disubstituted substrates such as cyclohexane-based cis- and trans-azide ketones 1i–1j could be diastereoselectively aminated to produce the 6,6-bicyclic structures 2i–2j in high yields (entries 9–10). As expected, the [Co( P1 )]-catalyzed amination could be well applied to electron-deficient tertiary C–H bonds as exemplified with azide ester 1k and azide ketone 1l , resulting in high-yielding formation of α,α-disubstituted α-amino acid and ketone 2k and 2l , respectively (entries 11–12).…”

“…3). 4 Since the α- and γ-amine groups in 4m are differentially protected, its further transformations should provide access to various α,γ-diamino acid derivatives. …”