A highly chemoselective Boc protection of amines using sulfonic-acid-functionalized silica as an efficient heterogeneous recyclable catalyst

Efficient N-Boc protection of amines by a reusable heterogeneous solid acid nanocatalyst at room temperature

“…Moreover, the high toxicity of DMAP and reagents derived from it limits their use [41]. These disadvantages can be avoided by electrophilic activation of (Boc) 2 [46], Cu(BF 4 ) 2 [47], Montmorillonite K10 [48], sulfonic-acid-functionalized silica [49,50], I 2 [51], indium(III) halides [52], tetrafluoroethylene (TFE) [53], protic ionic liquid [TMG][Ac] [54], and ionic liquid 1,3-disulfonic acid imidazolium hydrogen sulfate [55]. The design of new, milder and effective methods for N-Boc protection remains an active topic in synthetic chemistry.…”

Succinimide sulfonic acid (SuSA): an efficient and recyclable catalyst for the chemoselective N-Boc protection of amines

“…Di-tert-butyl dicarbonate [(Boc) 2 O] as a stable and commercially available reagent is widely used for this purpose [5,6]. Many methods have been reported to improve the rate of the N-Boc protection with (Boc) 2 O using basic or acidic catalysts [7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Although these procedures provide an improvement, most of them suffer from disadvantages such as long reaction times, tedious work-up, the use of corrosive or moisture-sensitive reagents, the formation of side-products during base-catalyzed reactions, difficulty in the preparation of the reagent, and using an excess of reagent in the case of Lewis acidcatalyzed reactions.…”

Saccharin sulfonic acid catalyzed N-Boc protection of amines and formation of tert-butyl ethers from alcohols

“…Many methods have been reported which were meant to improve the rate of the N-Boc protection with *Corresponding author. E-mail: shirini@guilan.ac.ir (Boc) 2 O using basic or acidic catalysts [7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Although these represent some improvement, most of them suffer from disadvantages such as long reaction times, tedious work-up, the use of corrosive or moisture sensitive reagents, formation of side-products during base-catalyzed reactions, difficulty in the preparation of the reagent, and using excess of reagent in the case of Lewis acid catalyzed reactions.…”