A recyclable fluorous hydrazine-1,2-bis(carbothioate) with NCS as efficient catalysts for acetalization of aldehydes

Abstract

Together with NCS, the catalyst showed a good activity in acetalization of aldehydes and alcohols. It could be recovered from the reaction mixture by fluorous solid-phase extraction (F-SPE) with excellent purity for direct reuse.

Acetalization of aldehydes and ketones over H4[SiW12O40] and H4[SiW12O40]/SiO2

“…For aliphatic aldehydes, the acetalization of alkyl aldehydes leads to excellent yields of >98% (Table 4, entries [13][14][15][16][17]. The acetalization of cyclohexanecarboxaldehyde proceeds efficiently with a yield of 97% (Table 4, entry 18).…”

“…The acetalization of aldehydes and ketones with alcohols or diols is a widely used approach in the pharmaceutical industry, such as drug design, carbohydrate chemistry, etc. [1][2][3] The currently used catalysts for the acetalization of aldehydes and ketones include HCl, tri-fluoroacetic acid (TFA) and p-toluenesulfonic acid (p-TSA), 4 solid acids, 5,6 functionalized silica, [7][8][9] acidic polymers, 10,11 Lewis acids, 12 metal catalysts, [13][14][15][16] organocatalysts, 17 and kaolintic clay. 18 However, the reported catalytic systems have the following disadvantages and potential technological and environmental problems, which, in the long run, cannot meet the green and sustainable chemistry requirements because (1) the used inorganic acids, such as H 2 SO 4 , HCl, p-toluenesulfonate etc., are corrosive; (2) an excess amount of drying agents, such as silica gel, montmorillonite and molecular sieve, etc., are needed; and (3) the selectivity is usually poor.…”

Hydrogen-Bond-Assisted Organocatalytic Acetalization of Secondary Alcohols: Experimental and Theoretical Studies

“…The latter characteristic is particularly applicable to the open-chain acetals (acyclic acetals) that have received special attention due to their lability, as compared to cyclic O , O -acetals, making them useful in multistep synthesis (e.g., when one needs to cleave an acetal under mild conditions). However, the targeted synthesis of the acyclic acetals from secondary alcohols is rarely reported, − even though these substrates are useful in organic synthesis because they offer alternative reactivity to the commonly used methanol or ethanol derivatives. Acyclic acetals derived from secondary alcohols can be used in tandem with methyl acetals for the selective protection and deprotection of a carbonyl group in the presence of the other carbonyl-containing functionality.…”

Visible-Light-Induced Acetalization of Aldehydes with Alcohols

“…Protection of carbonyl compounds such as aldehydes and ketones via acetal or ketal formation has been a common and powerful tool in multistep synthesis . As a consequence, numerous endeavors have been devoted to the protection of carbonyl compounds . Because the formation and hydrolysis of acetal are in equilibrium, typical procedures for acetalization always require the use of a corrosive acid catalyst, extended reaction times, or environmentally unfavorable solvents .…”