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Enantioselective Hydrothiolation: Diverging Cyclopropenes through Ligand Control

Shaozhen Nie, Alexander Lu, Erin L. Kuker and Vy M. Dong*

*Department of Chemistry, University of California, Irvine, Irvine, California 92697, United States, Email: dongvuci.edu

S. Nie, A. Lu, E. L. Kuker, V. M. Dong, J. Am. Chem. Soc., 2021, 143, 6176-6184.

DOI: 10.1021/jacs.1c00939


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Abstract

Cyclopropenes undergo Rh-catalyzed hydrothiolation to provide cyclopropyl sulfides or allylic sulfides. The choice of bisphosphine ligand dictates whether the pathway involves ring-retention or ring-opening. Whereas the use of Josiphos ligands provides cyclopropyl sulfides in high enantio- and diastereoselectivities, DTBM-BINAP generates allylic sulfides with high enantio- and regiocontrol.

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proposed mechanism



Ring-Opened General Procedure A:

In a N2-filled glove box, [Rh(cod)Cl]2 (1.2 mg, 0.0025 mmol), ligand (5.9 mg, 0.0050 mmol), and DCE (0.30 mL) were added to a 1-dram vial containing a stir bar. The resulting mixture was stirred for 10 min. Thiol (11.0 mg, 0.10 mmol) was added followed by cyclopropene (0.10 mL, 1.2 M solution in DCE, 0.12 mmol) to initiate the reaction. The mixture was held at 0C until no starting material was observed by TLC. The regioselectivity ratio was determined by 1H NMR analysis of the unpurified reaction mixture. Isolated yields (obtained by column chromatography on silica gel or preparative thin-layer chromatography) of the title compound are reported.


Key Words

allylic sulfides


ID: J48-Y2021