Sulfamic Acid‐Catalyzed Thioacetalization of Aldehydes under Solvent and Metal‐Free Conditions

Abstract

Herein, we have reported a straightforward methodology for the synthesis of dithioacetals through a metal‐free catalyzed reaction of aldehydes with thiols. In this regard, sulfamic acid proved to be a very efficient catalyst for the preparation of desired products under conventional heating as well as ultrasound irradiation. Generally, the desired products were obtained with reasonable yields through a thioacetalization process, under mild reaction conditions. Noteworthy, sulfamic acid could be recovered from the reaction by simple filtration and it was reused in further reactions and it showed good catalytic activity until the third cycle. In addition, a series of control experiments have also been performed and a plausible reaction mechanism has been illustrated.

The use of ultrasound in the South Cone region. Advances in organic and inorganic synthesis and in analytical methods

“…In 2020, Leitemberger et al [41] at Universidade Federal do Rio Grande (Brazil) reported an efficient methodology for the ultrasound-assisted synthesis of dithioacetals ( 110 ) through a solvent and metal-free catalyzed reaction of aldehydes ( 109 ) with thiols ( 108 ) ( Scheme 30 ). The sulfamic acid, as catalysts, proved to be efficient and it could be recovered and reused (until the third cycle) for the preparation of the desired products.…”

A convenient and mild protocol for preparation of α –trimethylsilyloxyphosphonates using sulfamic acid and their oxidation to α – ketophosphonates in the presence of N-bromosuccinimide

“…14 Only a limited number of effective and easily accessible reagents have been reported for silylation of αhydroxyphosphonates [15][16][17][18] which include Lewis acids such as I2 16 or M (OTf)X. 17,18 As a part of research programme in our laboratory on utilization of solid acid catalysts in organic transformations in general , 19,20 and investigations pertaining to sulfamic acid (SA) [21][22][23][24][25][26][27][28][29][30][31][32][33] in particular, we planned to test the utility of SA as a protic acid catalyst for silylation of α-hydroxyphosphonates using hexamethyldisilazane (HMDS) as the silylating agent to obtain α-trimethylsilyloxyphosphonates as well as a catalyst for their deprotection to regenerate parent αhydroxyphosphonates (Scheme 1). Concerning the preparation of α-ketophosphonates, literature survey revealed that there are two predominent methods viz; (i) the Michaelis-Arbuzov reaction between an acid chloride and a trialkylphosphite and (ii) the oxidation of easily accessible α-hydroxyphosphonates.…”

Copper-catalyzed thioketalization of enones featuring trifluoromethyl groups

“…Most methods have adopted Bronsted or Lewis acid catalysis to activate ketone and obtained thioketal. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Researchers have discovered catalysts, such as I 2 , 3 InI 3 , 4 TiCl 4 , 5 InCl 3 , 6,7 InBr 3 , 8 BF 3 $OEt 2 , 9 AgOTf, 10 Hf(OTf) 4 , 11 In(OTf) 3 , 12 TMSCl, 13 NH 2 SO 3 H, 14 DBSA, 15 Cu(DS) 2 , 16 and (COOH) 2 (ref. 17) working well in thioketalization.…”