Enantioselective Organocatalyzed Direct α-Thiocyanation of Cyclic β-Ketoesters by N-Thiocyanatophthalimide

Abstract

A new electrophilic thiocyanation reagent, N-thiocyanatophthalimide, was synthesized and applied to the first example of catalytic asymmetric electrophilic α-thiocyanation of various cyclic β-ketoesters by the bifunctional cinchona alkaloid catalysis. Thus, a variety of chiral α-thiocyanato β-ketoesters with a quaternary carbon center have been achieved in excellent yields (up to 99%) and high enantioselectivities (up to 94% ee) in a convenient manner.

Access to Isothiazolones from Simple Acrylamides by Pd-Catalyzed C–H Bond Activation

“…PdCl2 was purchased from Sigma-Aldrich Ltd. Dry DMF (N,N-Dimethylformamide, in sealed bottle with molecular sieves) was purchased from Acros Organics Ltd. Reagent I was synthesized according to the literature procedure. 13 Acrylamides 1a, 10c 1b, 14 1c, 10c 1e-1f, 10c 1g, 14 1h-1i, 10c 1j, 14 1k-1l, 10c 1m, 14 1n, 10c 1p, 14 1q-1r, 10c 1s, 15 1t, 10c 1u 14 were synthesized according to the preview reports in the literature. Starting materials 1v, 16 3, 16 4 17 and 5 10b were prepared according to literature procedures.…”

“…Removal of the solvent under vacuum and purification of the residue by Biotage afforded the desired product 2H). Note that the proton of OH was not visible 13. C{ 1 H} NMR (75.5 MHz, CDCl3): δ 165.9, 148.3, 145.6, 141.4, 138.6, 136.2, 135.9, 134.4, 128.4, 127.9, 127.3, 127.1, 121.9, 121.9, 121.5, 116.7, 64.9.…”

“…Hz, 2H), 7.60-7.32 (m, 4H), 4.08 (s, 3H) 13. C{ 1 H} NMR (75.5 MHz, CDCl3): δ 167.1, 152.1, 150.7, 143.5, 136.0, 132.4, 131.3, 131.1, 130.3, 128.5, 128.1, 126.7, 124.9, 123.6, 123.1, 122.3, 61.9.…”

Ag/Pyridine Co-Mediated Oxidative Arylthiocyanation of Activated Alkenes

“…So far, the reported approaches for the preparation of alkyl thiocyanates mainly focused on the nucleophilic [ 10 , 11 , 12 , 13 ] and electrophilic [ 14 , 15 , 16 ] substitution of prefunctionalized alkyl substrates with appropriated thiocyanation reagent and the direct thiocyanation of alkyl C–H bonds via oxidative functionalization [ 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. However, in these transformations, only a C–S bond is formed.…”

SYNTHESIS AND HETEROCYCLIZATION OF FUNCTIONALIZED Α-Thiocyanothcarbonyl COMPOUNDS

“…К такого рода реагентам относятся тиоционатокарбонильные соединения, которые в последнее время широко применяются в синтезе гетероциклических соединений, среди которых встречаются вещества с ярко выраженными биологическими свойствами. Наиболее общий метод синтеза алкил-и арилтиоцианатов состоит во взаимодействии соответствующих галогенидов, сульфатов или сульфанатов с тиоцианатами щелочных металлов [1][2][3][4][5][6][7][8][9][10][11][12][13]. Несмотря на относительно хорошие выходы в этих реакциях (65-85%), основной продукт реакции часто бывает загрязнен изомерным изотиоцианатом, особенно в тех случаях, когда реакция протекает по механизму SN1.…”