Efficient, solventless N-Boc protection of amines carried out at room temperature using sulfamic acid as recyclable catalyst

Preparation, characterization and application of succinimidinium hydrogensulfate ([H-Suc]HSO4) as an efficient ionic liquid catalyst for the N-Boc protection of amines

“…These include yttria-zirconia, 33 Zn ( 43 and indium(III) halides. 44 However, long reaction times, unsatisfactory yields, and limited applicabilities are drawbacks in several methods.…”

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.…”

Synthesis and Crystal Structure Determination of [H2‐cryptand 222](Br3)2: A Unique Tribromide Catalyst for the Catalytic Chemoselective N‐Boc Protection of Amines

“…29,30 Various reagents and methods have been developed for N-tert-butoxycarbonylation of amines. 31,32 Commercially available di-tert-butyl dicarbonate (diboc) is an efficient reagent for clean and rapid introduction of the boc-protecting group. [33][34][35] In this paper, we report the synthesis and structural characterization of [H 2 -cryptand 222](Br 3 ) 2 and show that it is as an excellent catalyst for the selective tert-butoxycarbonylation of various amines using diboc.…”