An efficient method for the cleavage of p-methoxybenzylidene (PMP), tetrahydropyranyl (THP) and 1,3-dithiane protecting groups by Selectfluor™
Junjie Liu and Chi-Huey Wong*
*Department of Chemistry and the Skaggs Institute for Chemical Biology, The
Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037,
USA, Email: wongscripps.edu
J. Liu, C.-H. Wong, Tetrahedron Lett., 2002, 43, 4037-4039.
DOI: 10.1016/S0040-4039(02)00740-2
Abstract
A new and efficient method for the cleavage of the PMP, THP and 1,3-dithiane protecting groups with Selectfluor™ has been developed.
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Details
The document presents a novel method developed by Junjie Liu and Chi-Huey Wong for efficiently cleaving p-methoxybenzylidene (PMP), tetrahydropyranyl (THP), and 1,3-dithiane protecting groups using Selectfluor™. Selectfluor™ (1-chloromethyl-4-fluoro-1,4-diazoniabicyclo [2,2,2] octane bis(tetrafluoroborate)) is an electrophilic fluorinating reagent known for its high yield in fluorinating electron-rich carbon centers. The method exploits Selectfluor™'s electrophilic and oxidative properties to achieve deprotection under mild conditions. For PMP and THP groups, deprotection is completed in 5 hours at room temperature using solvents like CH3CN or CH3NO2 with 5% water content, resulting in high yields. The 1,3-dithiane group can be cleaved in less than 5 minutes with 2.5 equivalents of Selectfluor™, also yielding high results. This method is advantageous due to its mild conditions, high efficiency, water solubility, non-toxicity, and cost-effectiveness of Selectfluor™. The study suggests that the fluorine group in Selectfluor™ may act as a Lewis acid in these reactions, although other mechanisms are not ruled out. Further research is being conducted to explore additional applications of this method in synthetic chemistry.
Key Words
protecting groups, Dithianes, THP, PMP, cleavage of acetals
ID: J72-Y2002-900