Palladium-Catalyzed Synthesis of N-Aryl Carbamates

Abstract

An efficient synthesis of aryl carbamates was achieved by introducing alcohols into the reaction of palladium-catalyzed cross-coupling of ArX (X = Cl, OTf) with sodium cyanate. The use of aryl triflates as electrophilic components in this transformation allowed for an expanded substrate scope for direct synthesis of aryl isocyanates. This methodology provides direct access to major carbamate protecting groups, S-thiocarbamates, and diisocyanate precursors to polyurethane materials.

Structural Reevaluation of the Electrophilic Hypervalent Iodine Reagent for Trifluoromethylthiolation Supported by the Crystalline Sponge Method for X‐ray Analysis

“…As part of our work on the synthesis of aryl isocyanates, [10] we were interested in developing new reagents based on the benziodoxole motif for isocyanate and isothiocyanate group transfer chemistry. We anticipated that the ambidentate cyanate and thiocyanate nucleophiles could potentially react with reagent 3 at either the nitrogen or group 16 element (oxygen or sulfur) nucleophilic sites.…”

“…Based on these data, Shen proposed that 1 contains the sulfur-bound hypervalent iodine motif, similar to all previously reported benziodoxole and benziodoxolone transfer reagents ( Figure 1). [2][3][4][5][6][7][8][9] As part of our work on the synthesis of aryl isocyanates, [10] we were interested in developing new reagents based on the benziodoxole motif for isocyanate and isothiocyanate group transfer chemistry. We anticipated that the ambidentate cyanate and thiocyanate nucleophiles could potentially react with reagent 3 at either the nitrogen or group 16 element (oxygen or sulfur) nucleophilic sites.…”

A Concise Flow Synthesis of Efavirenz

“…Similar to Buchwalds findings for the analogous intermolecular palladium-catalyzed reaction, the loss of reactivity may result from the formation of an inactive copper isocyanate species. [20] To facilitate adaption to a flow process, copper(I) sources with better solubility were also tested; whereas (CuOTf) 2 ·benzene provided a lower yield, [Cu(MeCN) 4 ]BF 4 performed slightly better (entries 6 and 7). We were surprised that Cu II catalysts were the most effective and robust catalysts for this reaction (entries 8 and 9).…”

“…CuI (20) DMEDA (1:2) trace 2 [c] CuI (20) phen (1:2) 0 3 [c] CuI (20) CyDMEDA (1:2) 12 4 CuI (20) CyDMEDA (1:4) 42 5 [d] CuI (20) CyDMEDA (1: CuI (20) CyDMEDA ( concentrations and permitted the use of smaller amounts of the Cu 0 additive (entries 6-8). Pure rac-Efavirenz was thus isolated in 62 % yield (entry 9).…”

One-Pot Three-Component Synthesis of Novel Carbamate Compounds Mediated by Zinc Powder

“…直接利用 CO 2 [7] 或 CO [8] 对胺的羰化反也能合成氨基甲酸酯, 但此 方法通常需在高温或高压条件下进行, 近年来利用 Lossen [9] , Hofmann [10] , Curtius [11] 重排反应合成氨基甲酸 酯类化合物的方法相继被报道. 氰酸盐、醇、芳基卤或 芳基硼酸三组分在过渡金属铜 [12] 或钯 [13] …”