P-S Bond Formation
Visible-light photoredox catalysis achieved a dehydrogenative coupling of phosphines and thiophenols at room temperature. Key to this success is the use of benzaldehyde as a soft oxidant, which avoids phosphine oxidation. Furthermore, an unexpected dealkylative coupling of secondary and tertiary alkylphosphines with thiophenols is observed.
X. Wang, C. Xia, L. Wu, Org. Lett., 2020, 22, 7373-7377.
In a Pd-catalyzed dehydrogenative phosphorylation, various thiols couple readily with H-phosphonates, H-phosphinates, and secondary phosphine oxides, to provide valuable phosphorothioates including P-chiral compounds. A plausible mechanism is proposed.
Y. Zhu, T. Chen, S. Li, S. Shimada, L.B. Han, J. Am. Chem. Soc., 2016, 138, 5825-5828.
Using L-proline as the ligand for a Cu-catalyzed coupling of sulfuryl chloride with P(O)-H compounds decreased the precatalyst loading, broadened the substrate scope and greatly promoted the efficiency of the coupling reaction. Moreover, gram-scale preparation, easy-to handle and recyclable catalyst featured this transformation.
X. Zhang, D. Wang, D. An, B. Han, X. Song, L. Li, G. Zhang, L. Wang, J. Org. Chem., 2018, 83, 1532-1537.
Tetrabutylammonium iodide (TBAI) catalyzes an aerobic oxidative cross-dehydrogenative coupling (CDC) of sulfonyl hydrazides with secondary phosphine oxides in the presence of atmospheric oxygen. This metal-free, efficient and practical approach provides an array of diverse phosphinothioates in very good yields.
T. Liu, Y. Zhang, R. Yu, J. Liu, F. Cheng, Synthesis, 2020, 52, 253-262.