Switchable Divergent Synthesis in Gold-Catalyzed Difunctionalizations of o-Alkynylbenzenesulfonamides with Aryldiazonium Salts

Abstract

Gold-catalyzed difunctionalizations of o-alkynylbenzenesulfonamides with aryldiazonium salts are reported herein. Upon irradiation with the blue LEDs, benzosultam products were formed via aminoarylation accompanied by the release of N 2 . Without irradiation, aryldiazonium salts were engaged as efficient electrophiles, facilitating electrophilic deaurations of the vinyl-Au(I) intermediates, followed by tautomerization to give the N-aryl-substituted α-imino (E)-hydrazones. The regioselectivities of 6endo-dig and 5-exo-dig cyclizations were excellent.

Ortho-Phosphinoarenesulfonamide-Mediated Staudinger Reduction of Aryl and Alkyl Azides

“…All reactions were conducted under an atmosphere of nitrogen in oven-dried glassware unless otherwise noted. 2-Iodo-5-methylbenzenesulfonamide was prepared according to the literature methods [ 25 , 26 ]. Bis(4-methoxyphenyl)phosphane [ 27 , 28 ] and organic azides except 1j , 1s, and 1w were prepared according to the literature methods (for 1a [ 29 ], 1b-i , 1k-m , 1o , 1p , 1r , 1t-v [ 30 ], 1n and 1q [ 31 ]).…”

One-Pot Synthesis of Polycyclic Sultams Enabled by Gold-Catalyzed Hydroamination of o-Alkynylbenzenesulfonamides and Subsequent Iodine(III)-Mediated Counteranion-Assisted Intramolecular Annulation

“…Based on a previous report, 13 2-([1,1′-biphenyl]-2ylethynyl)benzenesulfonamide (1aa) was selected as a model substrate to examine the practicability of our hypothesis (Table 1). We initially performed an experiment with 1aa in the presence of 10 mol % PPh 3 AuNTf 2 in tetrahydrofuran.…”

“…As a result, these heterocyclic structures play a crucial role in medicinal, organic synthetic, and agricultural fields and have attracted great attention from synthetic chemists for a long time. Consequently, various methodologies, particularly those employing transition metals such as Pd, Rh, Co, Ag, Au, Ni have been developed to access these sultam skeletons. These facile and effective methods usually provide the desired sultams through fewer synthetic steps.…”

Ligand-Assisted Gold-Catalyzed Efficient Alkynylative Cyclization with Terminal Alkynes Using H2O2 as Oxidant

“…To avoid the burden of such waste-generating oxidants, a Au/Pd dual catalytic system proved to be effective for the cyclization-functionalization process, however the very low number of reports suggest that its general application remains challenging. 5,6 In addition, the use of special pre-functionalized substrates such as aryldiazonium salts, [7][8][9][10][11] alkynyl hypervalent iodine reagents, [12][13][14][15][16] alkynyl halides, [17][18][19] etc. also gave access to Au I /Au III catalytic cycles without external oxidants to afford cyclic functionalized molecules.…”

“…Although the use of external oxidants is avoided, its limitations are also significant, such as air sensitivity, the need for expensive photosensitizers and special photoreactors. [7][8][9][10][11]17,19 Furthermore, the synthesis of the applied reagents is not straightforward, [12][13][14][15][16] resulting in low atom economy and high costs.…”