Synthesis of N,S-acetals

Recent Literature

A mild and chemoselective coupling of easily accessible thiosulfonates and 2-azaallyls provides α-amino sulfides in good yields via a tandem process of single-electron transfer and radical-radical coupling.
S. Duan, Y. Zi, Y. Du, J. Cong, X. Sun, H. Jing, J. Zhao, W. Chen, X. Yang, Org. Lett., 2023, 25, 3687-3692.

Enantioenriched N,S-acetals can be prepared using chiral BINOL phosphoric acids. The reaction combines electron-rich and electron-deficient aromatic N-acyl imines with broad range of aliphatic and aromatic thiols to generate products in excellent yield and enantioselectivity. The addition reaction could also be achieved with an exceptional substrate to catalyst (S/C) molar ratio.
G. K. Ingle, M. G. Mormino, L. Wojtas, J. C. Antilla, Org. Lett., 2011, 13, 4762-4765.

A photoinduced, iron(III) chloride-catalyzed C-H activation of N-methyl amides and ethers leads to the formation of C-S and C-Se bonds. Tertiary amides, sulfonamides, and carbamates can be converted into the corresponding amido-N,S-acetal derivatives in good yields. This transformation proceeds through a hydrogen atom transfer (HAT) involving chlorine radical intermediates.
B. Niu, K. Sachidanandan, M. V. Cooke, T. E. Casey, S. Laulhé, Org. Lett., 2022, 24, 4524-4529.

A nickel-catalyzed decarbonylation of α-amino acid thioester provides efficient and expedient access to α-aminosulfides with excellent chemoselectivity. This aminomethylation of mercaptans shows good functional-group compatibility, tolerates a wide range of electron-withdrawing and electron-donating substituents, and enables the synthesis of α-aminosulfides even at a gram scale.
J.-Y. Zhou, R. Tian, Y.-M. Zhu, J. Org. Chem., 2021, 86, 12148-12157.

An efficient, rhodium-catalyzed chain-walking hydrothiolation process for internal alkenes exclusively affords N,S-acetals in good yields. An amide-directing group is essential for this regioconvergent hydrothiolation.
N. Hikida, Y. Yoshimi, H. Suzuki, Org. Lett., 2024, 26, 2500-2504.