Dehydrative Synthesis of Functionalized Skipped Dienes from Stabilized Phosphonium Ylides and Allylic Alcohols in Water

Abstract

A mild and extra activator-free dehydrative alkylation of stabilized phosphonium ylides with allylic alcohols in water is developed in the presence of [Pd(allyl)Cl] 2 /dppf catalyst. A wide range of aryl, heteroaryl, alkyl and even allylic tertiary alcohols can readily react with stabilized phosphonium ylides with high regioselectivity for the efficient synthesis of functionalized skipped dienes in moderate to high yields. The role of water was investigated by means of a high-resolution mass spectrum and diffusion-ordered spectroscopy nuclear magnetic resonance, and the results revealed that water might play a crucial role in the formation of the p-allylpalladium complex via hydrogen bond. However, the present method is not suitable for water-sensitive phosphonium ylides.

Mild and Regioselective Bromination of Phenols with TMSBr

“…Then 1 H NMR titration techniques were employed to investigate the possible interaction between phenol and thioether,, revealing O‐H ··· S hydrogen bond may be formed between phenol and thioether, but not between anisole/toluene and thioether, which is well consisted with the experimental results (Table , runs 20–21) . Therefore, the high regioselectivity of this new method may be ascribed to the temporary steric hindrance effect from by‐product.…”

“…Despite the wide applications of by‐products as a catalyst, additive, or reagent in tandem reactions, by‐product dimethyl sulfide generated from the oxidative bromination reaction of YBr/DMSO was generally disposed as toxic and smelly waste. With our continuous interest in regioselective halogenation and hydrogen chemistry, herein, we wish to report a mild and regioselective bromination of phenols with TMSBr (Scheme C). The desired para ‐brominated phenols could be obtained in high selectivity (up to 99:1) by using sulfoxides bearing sterically hindered substituents.…”

Palladium-Catalyzed Dehydrative Cross Couplings of Stabilized Phosphorus Ylides with Allylic Alcohols

“…(E)-1-苯基-4-苯甲酰基-1,4-戊二烯(3a) [10] : 无色油. 1 H NMR (600 MHz, CDCl 3 ) δ: 7.82～7.76 (m, 2H), 7.57～7.52 (m, 1H), 7.47～7.42 (m, 2H), 7.38 (d, J＝7.8 Hz, 2H), 7.31 (t, J＝7.8 Hz, 2H), 7.22 (t, J＝7.2 Hz, 1H), 6.52 (d,J＝15.8 Hz,1H),6.31 (dt,J＝15.8,7.2 Hz, 1H), 5.95 (s, 1H), 5.72 (s, 1H), 3.39 (d, J＝7.2 Hz, 2H); 13 C NMR (150 MHz, CDCl 3 ) δ: 197.…”

“…1 H NMR (600 MHz, CDCl 3 ) δ: 7.82～7.76 (m, 2H), 7.57～7.52 (m, 1H), 7.47～7.42 (m, 2H), 7.38 (d, J＝7.8 Hz, 2H), 7.31 (t, J＝7.8 Hz, 2H), 7.22 (t, J＝7.2 Hz, 1H), 6.52 (d,J＝15.8 Hz,1H),6.31 (dt,J＝15.8,7.2 Hz, 1H), 5.95 (s, 1H), 5.72 (s, 1H), 3.39 (d, J＝7.2 Hz, 2H); 13 C NMR (150 MHz, CDCl 3 ) δ: 197. 9, 146.6, 137.8, 137.4, 132.6, 132.4, 129.6, 128.7, 128.6, 127.4, 127.0, 126.7, 126.3, 35.5 [10] : 无色油. 1 H NMR (600 MHz 198.0, 159.1, 146.9, 137.8, 132.4, 132.0, 130.3, 129.6, 128.3, 127.4, 126.8, 124.4, 114.1, 55.4, 35.5 [10] : 无色油.…”

“…9, 146.6, 137.8, 137.4, 132.6, 132.4, 129.6, 128.7, 128.6, 127.4, 127.0, 126.7, 126.3, 35.5 [10] : 无色油. 1 H NMR (600 MHz 198.0, 159.1, 146.9, 137.8, 132.4, 132.0, 130.3, 129.6, 128.3, 127.4, 126.8, 124.4, 114.1, 55.4, 35.5 [10] : 无色油. 1 H NMR (600 MHz 198.0, 156.5, 146.9, 137.8, 132.3, 129.6, 128.3, 127.2, 126.7, 126.5, 120.7, 110.9, 55.6, 35.9; MS (EI) m/z: 278.…”