Lithium Trifluoromethanesulfonate (LiOTf) as a Recyclable Catalyst for Highly Efficient Acetylation of Alcohols and Diacetylation of Aldehydes under Mild and Neutral Reaction Conditions

Abstract

A variety of alcohols and aldehydes were reacted with acetic anhydride at room temperature in the presence of a catalytic amount of lithium triflate (LiOTf) to produce the corresponding esters and 1,1-diacetates, respectively, in good to excellent yields under essentially neutral reaction conditions. Sensitive functional groups such as PhCO(2)-, OMe, and OTBDMS ethers survived intact under the described reaction conditions.

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.…”

Acetonyltriphenylphosphonium Bromide (ATPB): A Versatile Reagent for the Acylation of Alcohols, Phenols, Thiols and Amines and for 1,1‐Diacylation of Aldehydes under Solvent‐Free Conditions

“…[27] The formation of a 1,1-diacetate is usually achieved by treatment of an aldehyde compound with acetic anhydride in the presence of an acid or Lewis acid, acting as a catalyst. The literature includes several reported methods employing various reagents such as LiOTf, [28] ceric ammonium nitrate, [29] InCl 3 , [30] H 2 NSO 3 H, [31] LiBF 4 , [32] H 2 SO 4 , [33] PCl 3 , [34] NBS, [35] I 2 , [36] TMSCl·NaI, [37] FeCl 3 , [38] and Bi(NO 3 ) 3 ·5H 2 O for similar transformations. [39] Some metal triflates (e.g., Cu(OTf) 2 [40] and Sc(OTf) 3 [41] ) have also been utilized as catalysts for the preparation of 1,1-diacetate derivatives from the corresponding aldehydes.…”

Silica immobilized sulfuric acid ([3-(propyl)sulfanyl]propyl]ester andN-propylsulfamic acid as recyclable catalysts for chemoselective synthesis of 1,1-diacetates

“…Appropriate nucleophiles can convert the acylal functionality into other functional groups (8,9). Generally, they are synthesized from acetic anhydride and aldehydes using strong protonic acids as catalysts, such as sulfuric (10), phosphoric (11), methanesulfuric (12), or perchloric acid (13), Lewis acids, such as FeCl 3 (2), PCl 3 (14), InCl 3 (15), ZrCl 4 (16) (23), Cu(OTf) 2 (24), Sc(OTf) 3 (25), LiOTf (26), and heterogeneous catalysts such as Nafion-H (27), expansive graphite (28), zeolites (29), montmorillonite clay (30,31), and supported reagents (32Á35). Other catalysts, such as iodine (36), N-bromosuccinimide (37), and trimethylchlorosilane/sodium iodide (38), have also been used for this transformation, but these procedures are often accompanied by longer reaction times, poor product yields, stringent conditions, good catalyst loading; require the use of toxic solvents; and so on.…”