Deprotection of dithioacetals with 30% hydrogen peroxide catalyzed by tantalum(V) chloride–sodium iodide or niobium(V) chloride–sodium iodide

Niobium(V) Chloride Catalyzed Oxidation of Dithioacetals with 30% Hydrogen Peroxide: A Concise Preparation of Bissulfonylmethylene Compounds

“…We also found that the reaction of 2 with 30% hydrogen peroxide catalyzed by Nb(V)-NaI or Ta(V)-NaI in ethyl acetate effectively afforded the corresponding carbonyl compounds 13,14) (Chart 3). The use of iodide ion (I − ) as the catalyst is essential to obtain the carbonyl compounds.…”

Recent Advances in the Synthesis of Acylsilanes

“…The 'I + equivalent' intermediate then reacts with 2silylated 1,3-dithianes through the sulfur atom allowing it to be easily deprotected to form acylsilanes. [14] Functionalized acylsilanes containing various substituents are known to be important compounds and useful synthetic building blocks. [6d,15] In 2011, Honda and co-workers reported the one-pot synthesis of cyclopropyl silyl ketones using silylcyclopropyl bromides 1 as starting material (Scheme 8).…”

Mild Deprotection of Dithioacetals by TMSCl / NaI Association in CH3CN

“…[23] This suggests that, as soon as aldehydes are formed after thioacetal deprotection, they add nucleophilic iodides, which may arise from TMSI slowly generated in the media according to an exchange Finkelstein reaction. [24] To show the interest of this process with respect to other previously reported methods using for examples HgO associated with BF 3 -Et 2 O, [25] 2,6-dicarboxy pyridinium chlorochromate (DCPCC) [26] or SbCl 5 [27] we have deprotected dithiolanes 1v and 1w by TMSCl/NaI in CH 3 CN (Scheme 2). The comparison of the yields obtained using the TMSCl/NaI mild association in CH 3 CN vs toxic oxidizing agent as HgO (86 % vs 65%), DCPCC (93% vs 70%) or SbCl 5 (93% vs 77%) supports well that this novel metal-free process is welcome since the yields in desired ketones are significantly higher and the reagents used for the deprotection are inexpensive, non-toxic and very easy to handle.…”