Rongalite

Abstract

This feature focuses on a reagent chosen by a postgraduate, highlighting the uses and preparation of the reagent in current research RongaliteCompiled by Jiu-Xi Chen Jiu-Xi Chen was born in 1982 in Wenzhou, Zhejiang Province, P. R. of China. He received his M. Sc. degree (2007) IntroductionRongalite (also known as sodium formaldehyde sulfoxylate or sodium hydroxymethanesulfinate) is a versatile, inexpensive and readily available reagent, which has been employed twenty years ago.1 It is commonly used in the textile industry as a decolorizing agent. Several reports are available in the literature demonstrating its utility in organic synthesis. For example, rongalite is capable of producing the perfluoroalkyl free radicals via dehalogenation of alkyl halides, 2-4 such as direct perfluoroalkylation of pyridines, 5 coumarins 6 and 2-quinolones. 7 It has been also used for the cleavage of diaryl disuldes and diselenides generating the corresponding chalcogenolate species in situ that then undergo facile ring opening and acylation, affording b-hydroxy sulfides, 8 thioesters and selenoesters, 9 respectively. It was also found to be a sulfoxylate dianion equivalent in the conversion of dihalides into sultine derivatives. [10][11][12][13][14][15] Rongalite is commercially available, but it can also be readily prepared by reaction of formaldehyde with sodium sulfite. 16 Scheme 1 Abstracts ) One-Pot Synthesis of Thioesters and Selenoester via Reaction of Diaryl Disulfides with Anhydrides:A simple, efficient and broadly applicable general method for the synthesis of thioesters in one step by acylation of diaryl disulfides with aromatic, aliphatic or cyclic anhydrides in the presence of rongalite and CsF has been developed. Furthermore, this method was applied to the synthesis of seleno esters. Rongalite is speculated to promote cleavage of diaryl disulfides generating chalcogenolate anions that then undergo facile acylation with anhydrides in the presence of CsF to afford the corresponding thioesters and selenoesters. (B) Highly Regioselective Ring Opening of Epoxides with Diaryl Disulfides for the Synthesis of b-Hydroxy Sulfides:Rongalite has successfully been used as initiator for the highly regioselective ring opening of epoxides with diaryl disulfides to the corresponding a-addition products in good to excellent yields. 18-19It should be noted that the thiolate anion attacks the epoxides derived from styrene to produce the corresponding a-addition products with high regioselectivity, instead of the b-addition regioisomer that could be formed from the attack of the nucleophile at the benzylic position. Synlett 2012, 23, 157-158 158 SPOTLIGHT

New Dimensions in Rongalite Chemistry: The Land of Opportunities in Organic Synthesis and Material Sciences

“…Although, the fruitful history of rongalite commonly known as sodium hydroxymethanesulfinate ( IUPAC name ) or sodium formaldehydesulfoxylate/sodium oxymethylene sulfoxylate is much older but the major advances of this multipurpose reagent were originally developed in the early 20 th century for the textile industry as a source of sulfoxylate ion (HSO 2 ¯). Indeed, in the realm of synthetic organic chemistry, rongalite has been labelled an “old dog” which can be taught “new tricks”, and it should be interesting to include this valuable and low toxic reagent into the challenging organic transformations . Rongalite (Figure ) which is water‐soluble and sold as dihydrate termed in French as “rongeage” which means discharge or decolorizing agent, whose X ‐ray crystal structure was first time studied by Truter .…”