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.
With Ni(OAc)2 as catalyst, an oxidative coupling of thiols and phosphonates to phosphorothioates with oxygen as oxidant proceeded very sluggishly with low yield, whereas adding non-redox-active metal ions such as Y3+ dramatically promoted the catalytic efficiency. Y(OTf)3 can obviously accelerate the activation of thiols by Ni(II) and next accelerate its reaction with phosphonate.
J.-W. Xue, M. Zeng, S. Zhang, Z. Chen, G. Yin, J. Org. Chem., 2019, 84, 4179-4190.
A NaBr-catalyzed coupling reaction of Bunte salts with phosphonates enables a simple, green, and efficient synthesis of of thiophosphates in good yields in the presence of an acid and hydrogen peroxide (30%).
C. Min, R. Zhang, Q. Liu, S. Lin, Z. Yan, Synthesis, 2018, 50, 2027-2030.
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.
A multicomponent reaction involving aryl boronic acids, elemental sulfur, and P(O)H compounds provides valuable S-aryl phosphorothioates and S-aryl phosphorodithioates in excellent yields. Moreover, this method can be easily scaled up.
J. Xu, L. Zhang, X. Li, Y. Gao, G. Tang, Y. Zhao, Org. Lett., 2016, 18, 1100-1103.
Green methods based on copper-catalyzed multicomponent reactions enable the synthesis of S-aryl phosphorothioates from diaryliodonium/arenediazonium salts, elemental sulfur, and R2P(O)H compounds in very good yields at room temperature. These transformations allow the direct formation of P-S and C-S bonds in one reaction.
L. Zhang, P. Zhang, X. Li, J. Xu, G. Tang, Y. Zhao, J. Org. Chem., 2016, 81, 5566-5573.
A simple and efficient method for the preparation of thiophosphates from benzenethiols involves copper(I) iodide catalyzed coupling of thiols with H-phosphonates in the presence of triethylamine. The reaction proceeds effectively via an aerobic dehydrogenative coupling to afford the corresponding thiophosphates in good yields.
B. Kaboudin, Y. Abedi, J.-Y. Kato, T. Yokomatsu, Synthesis, 2013, 45, 2323-2327.
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.