22, 23], (ii) reaction of ketals with H 2 O 2 in the presence of tungstic acid [24], or BF 3 ·Et 2 O [25], and (iv) peroxidation of ketones using an acidic solvent [26]. However, many of these methods have certain drawbacks including use of concentrated H 2 O 2 and excess acid, low yield, limited substrate range and production of mixtures of peroxidic products [27]. Also, poor selectivity and the presence of ozonesensitive groups in the substrates are further limitations in ozonolysis reaction. To avoid such limitations, recently, reactions of ketones and aldehydes with H 2 O 2 in the presence of Lewis acids in organic solvents have been reported. Among the Lewis acids, I 2 [28, 29], ceric ammonium nitrate (CAN) [30], CSA [31], NaHSO 4 ·SiO 2 [32], Re 2 O 7 [33], and PMA [34] have been reported as the catalysts in the synthesis of gem-dihydroperoxides with aqueous H 2 O 2 .In continuation of our efforts to explore new catalysts for synthesis of gem-dihydroperoxides [35,36]. Herein, we wish to introduce the sulfamic acid as a low-cost, green and effective recoverable solid catalyst in the synthesis of gemdihydroperoxides from ketones and aldehydes with 30 % aqueous H 2 O 2 at room temperature (Scheme 1).Sulfamic acid (SA) (NH 2 SO 3 H) is commercially available green heterogeneous catalyst that is solvable in water and has been used widely as an effective catalyst in organic synthesis [37,38]. ExperimentalSolvents, reagents, and chemical materials were obtained from Aldrich and Merck chemical companies and purified prior to use. Nuclear magnetic resonance spectra were recorded on JEOL FX 90Q using tetramethylsilane (TMS) as an internal standard. Infrared spectra were recorded on a PerkinElmer GX FT IR spectrometer (KBr pellets).Abstract Sulfamic acid has been used as an active, lowcost and reusable solid catalyst for conversion of ketones and aldehydes to corresponding gem-dihydroperoxides using 30 % aqueous hydrogen peroxide at room temperature. The reactions proceed with high rates and excellent yields.