Sn–bentonite-induced Baeyer–Villiger oxidation of 2-heptylcyclopentanone to δ-dodecalactone with aqueous hydrogen peroxide

Sn-based catalysts for Baeyer-Villiger oxidations by using hydrogen peroxide as oxidant

“…Thus, a different mechanism of BV oxidation from the traditional peroxide catalyzed oxidation mechanism can be outlined, in which actually the second step of carbonyl carbon activation is principally the same as the BV oxidation mechanism over Sn-beta-zeolite catalyst reported by Corma et al [40]. The catalytic mechanism of Sn-based cationic clay catalysts such as Sn-bentonite catalyst [90] and Sn-based anionic clay catalysts such as Sn-doped hydrotalcite (Sn/HT) catalyst [97], for BV oxidation of ketones follows this route (I) including two activation steps.…”

“…In addition, this type of catalytic mechanism is also applicable for Sn-based mesoporous catalysts such as Sn-MCM-41 [59,60], Sn-SBA-15 [64], Sn-MCM-48 [65], Sn-SBA-16 [71], Sn-MWW [77]. Sn-based cationic clay catalysts such as Sn-palygorskite [84,85], Sn-MMT [89], Sn-bentonite [90], and Sn-based polymer catalysts such as aminomethyl polystyrene resin supported tin complex (PS-Sn) [134], chloromethyl polystyrene supported dendritic Sn complexes catalyst (P-PAMAM-HBA (1.0G)-Sn(II)) [135], cellulose supported dendritic Sn complexes catalyst (P-PAMAM-HBA (2.0G)-Sn (II)) [136], chitosan supported dendritic Sn complexes [137], porous Sn(IV) phenylphosphonates (SnPP) [140].…”

“…While for the BV oxidation of 2-heptylcyclopentanone to δ-dodecalactone, the tin ion-exchanged bentonite (Sn-bentonite) seems to be a rather efficient and highly selective catalyst, as shown in Table 6, the conversion of 2-heptylcyclopentanone to δ-dodecalactone in high yield (81%) could be obtained at the Sn-bentonite catalyst with methanesulfonic acid (MSA) and sodium dodecyl sulfate (SDS) as the additives [90]. The possible reactions are shown in Scheme 2, in which the cycloketone is coordinated to the Lewis acid tin center to activate the carbonyl group first, similar to Sn-beta-zeolites [40], and then the peroxy acid resulting from the interaction between hydrogen peroxide and MSA attacks the electrophilic carbonyl carbon, thus, leading to the excellent results of the BV oxidation over Sn-bentonite [90].…”

“…The possible reactions are shown in Scheme 2, in which the cycloketone is coordinated to the Lewis acid tin center to activate the carbonyl group first, similar to Sn-beta-zeolites [40], and then the peroxy acid resulting from the interaction between hydrogen peroxide and MSA attacks the electrophilic carbonyl carbon, thus, leading to the excellent results of the BV oxidation over Sn-bentonite [90]. These Sn incorporated cationic clay materials are prospective catalysts for the wide applications in industry for BV oxidation of ketones for its low cost and facile synthesis.…”