A novel and highly efficient method for the silylation of alcohols with hexamethyldisilazane (HMDS) catalyzed by recyclable sulfonic acid-functionalized ordered nanoporous silica

Electron‐deficient vanadium(IV) tetraphenylporphyrin: A new, highly efficient and reusable catalyst for chemoselective trimethylsilylation of alcohols and phenols with hexamethyldisilazane

“…One disadvantage of HMDS is its poor silylating power in the absence of a suitable catalyst, needing forceful conditions and long reaction times in many cases. [10] To solve this problem, a variety of catalysts, including (CH 3 ) 3 SiCl, [11] ZrCl 4 , [12] ZnCl 2 , [13] K-10 montmorillonite, [14] LiClO 4 , [15] H 3 PW 12 O 40 , [16] iodine, [17] InBr 3 , [18] zirconium sulfophenyl phosphonate, [19] CuSO 4 .5H 2 O, [20] sulfonic acid-functionalized nanoporous silica, [21] MgBr 2 ·OEt 2 , [22] LaCl 3 , [23] poly(N-bromobenzene-1,3-disulfonamide) and N,N,N ,Ntetrabromobenzene-1,3-disulfonamide, [24] Fe(TFA) 3 , [25] Fe 3 O 4 , [26] (n-Bu 4 N)Br, [27] trichloroisocyanuric acid (TCCA), [28] HClO 4 -SiO 2 , [29] Pd [30] and ZrO(OTf) 2 , [31] have been reported for trimethylsilylation of alcohols and phenols. Although these procedures provide an improvement, many of the catalysts or activators need long reaction times, drastic reaction conditions or tedious workups, or are moisture-sensitive or expensive.…”

Continuous-Flow Alcohol Protection and Deprotection Reactions Catalyzed by Silica-Supported Sulfonic Acid

“…The continuous-flow protocol delivers much shorter reaction times, as the residence time is approximately 30 s at 40 μL/min. This compares very favorably to batch, where the protection of these alcohols typically takes at least 60 min [14].…”

“…Saidi and Azizi demonstrate the use of solid LiClO 4 for the same reaction under solvent-free conditions [13]. The reaction is also known to be catalyzed by silica-supported sulfonic acids [14]. We hypothesized that it would be possible to conduct these reactions in continuous flow using solid-supported sulfonic acids.…”

Rapid, highly efficient and chemoselective trimethylsilylation of alcohols and phenols with hexamethyldisilazane (HMDS) catalyzed by reusable electron‐deficient tin(IV)porphyrin

“…However, the main disadvantage of HMDS is its poor silylating power in the absence of a suitable catalyst which needs forceful conditions and long reaction times in many cases. [8] To solve this problem, a variety of catalysts including (CH 3 ) 3 SiCl, [9] sulfonic acids, [10] ZnCl 2 , [11] K-10 montmorilonite, [12] LiClO 4 , [13] H 3 PW 12 O 40 , [14] iodine, [15] InBr 3 , [16] zirconium sulfophenyl phosphonate, [17] CuSO 4 .5H 2 O, [18] sulfonic acid-functionalized nanoporous silica, [19] MgBr 2 ÐOEt 2 , [20] LaCl 3 , [21] poly(N-bromobenzene-1,3-disulfonamide) and N,N,N 0 ,N 0 -tetrabromobenzene-1,3-disulfonamide, [22] Fe(TFA) 3 , [23] Fe 3 O 4 , [24] (n-Bu 4 N)Br [25] and ZrO(OTf) 2 [26] have been reported. Although these procedures provide an improvement, many of these catalysts or activators need long reaction times, drastic reaction conditions or tedious workups, are moisture sensitive or have an expensive catalyst.…”