An efficient method for the chemoselective synthesis of acylals from aromatic aldehydes using bismuth triflate

Abstract

Aromatic aldehydes are smoothly converted into the corresponding acylals in good yields in the presence of 0.10 mol% Bi(OTf)3oxH20. Ketones are not affected under the reaction conditions. The highly catalytic nature of bismuth triflate and the fact that it is relatively non-toxic, easy to handle and insensitive to small amounts of air and moisture makes this procedure especially attractive for large scale synthesis.

ZSM-5-SO3H as a novel, efficient, and reusable catalyst for the chemoselective synthesis and deprotection of 1,1-diacetates under eco-friendly conditions

“…Also, several methods have been developed for the preparation of 1,1-diacetates by employing various Lewis acids such as Fe(NO 3 ) 3 .9H 2 O [13], cupric sulfate [14], In(OTf) 3 [15], P 2 O 5 /Al 2 O 3 [16], LiOTf [17], Bi(NO 3 ) 3 [18], Keggin heteropolyacid [19], Al(HSO 4 ) 3 [20], titaniummodified MCM-41 [21], sulfuric acid [3-(3-silicapropyl) sulfanyl]propyl ester [22], silica-bonded N-propylsulfamic acid [23], polymer-supported gadolinium triflate [24], different solid acids [25], and Brønsted acidic ionic liquids under ultrasonic irradiation [26]. However, many of these existing methodologies suffer from one or more of the following disadvantages: prolonged reaction times and low yields [13], high temperatures [19], use of harmful organic solvents [19,27,28], use of moisture-sensitive and costly catalysts (e.g., triflates) [15,24], and use of excess Ac 2 O [29]. Also, very few reports are applicable to both the synthesis as well as deprotection of 1,1-diacetates [30][31][32].…”

Reinvestigation of the Mechanism of gem‐Diacylation: Chemoselective Conversion of Aldehydes to Various gem‐Diacylates and Their Cleavage under Acidic and Basic Conditions

“…Some of the reagents and catalysts that have been employed include H 2 SO 4 , [4] HClO 4 , [5] H 3 PO 4 , [6] CH 3 SO 3 H, [7] PCl 3 , [8] FeSO 4 ·xH 2 O [9] I 2 , [10] TMSCl-NaI, [11] NBS, [12] CAN, [13] InCl 3 , [14] WCl 6 , [15] LiBF 4 , [16] Zn(BF 4 ) 2 , [17] ZrCl 4 , [18] CoCl 2 , [19] NH 2 SO 3 H, [20] Bi(OTf) 3 ·xH 2 O, [21] Sc(OTf) 3 , [22] LiOTf, [23] Cu(OTf) 2 , [24] FeCl 3 , [1b,25] and sulfated zirconia. [26] Some solid acidic catalysts, for example NafionH, [27] zeolite, [28] montmorillonite clay, [29] graphite, [30] Fe 3ϩ on montmorillonite, [31] PVC-FeCl 3 [32] WellsϪDawson acid, [33] zirconium sulfenyl phosphonate, [34] AlPW 12 O 40 [35] and Amberlite15, [36] have also been used for this purpose.…”

H-Mordenite zeolite as an efficient, rapid and recyclable catalyst for chemoselective synthesis o

“…Various methods have been reported in the literature for the synthesis of 1, 1-diacetate from strong acids including sulfamic acids [5], sulphuric acid [6], methane sulphuric acid [7] lewis acids such as lithium bromide [8], FeCl3 [9], PCl3 [10], NBS [11], expensive graphite [12], zeolite HSZ-360 [13], montmorillonite clay [14], Sulphate Zirconia [15], Cu(OTf)2 [16], Sc(OTf)3 [17], and ZrCl4 [18], P2O5 [19], sodium lithium perchlorate [20] [24], aluminum chloride [25], and certain transition metal compounds and complexes [26] which are more effective for this conversion. However, above these methods have some main limitations such as formation of low yield, long reaction time, high temperature, strong acidic condition, expensive reagents, corrosive and highly toxicity.…”