Cu-catalyzed cross-coupling reactions of vinyl epoxide with organoboron compounds: access to homoallylic alcohols

Abstract

Copper-catalyzed cross-coupling reactions of vinyl epoxide with arylboronates to obtain aryl-substituted homoallylic alcohols are described.

Photoexcited Palladium-Initiated Remote Desaturation of N-Alkoxypyridinium Salts

“…1 H NMR (400 MHz, Chloroform-d) δ 7.80–7.76 (m, 3H), 7.69 (s, 1H), 7.58 (dd, J = 8.7, 1.8 Hz, 1H), 7.47–7.40 (m, 2H), 6.66 (d, J = 15.9 Hz, 1H), 6.34 (dt, J = 15.8, 7.1 Hz, 1H), 3.80 (t, J = 6.3 Hz, 2H), 2.57–2.52 (m, 2H), 1.51 (s, 1H); 13 C­{ 1 H} NMR (101 MHz, Chloroform-d) δ 134.7, 133.6, 132.9, 132.8, 128.1, 127.9, 127.6, 126.8, 126.2, 125.8, 125.7, 123.4, 62.1, 36.5. The spectroscopic properties were consistent with the data available in the literature …”

“…13 C and 19 F NMR spectra are fully decoupled by broad band proton decoupling. High Resolution Mass spectra were obtained from micro TOF-Q 134 High-resolution MS. Optical rotations were reported as follows: [α] 26 D (c g/100 mL, solvent). General Procedures A for The Remote Desaturation.…”

“…The spectroscopic properties were consistent with the data available in the literature. 26 ( .4, 129.0 (q, J = 32.5 Hz), 126.2, 125.5 (q, J = 3.8 Hz), 124.2 (q, J = 272.7 Hz), 61.9, 36.4; 19 F NMR (376 MHz, Chloroform-d) δ −62.5. The spectroscopic properties were consistent with the data available in the literature.…”

“…Purification of the residue by silica gel with petroleum ether and ethyl acetate (R f = 0.2, PE/EA = 5:1) afforded the title compound 2h as a colorless oil, 12.7 mg, 72% yield. 1 H NMR (400 MHz, Chloroform-d) δ 9.97 (s, 1H), 7.82 (d, J = 8.3 Hz, 2H), 7.50 (d, J = 8.2 Hz, 2H), 6.56 (d, J = 15.9, 1H), 6.42 (dt, J = 15.9 Hz, J = 7.0 Hz, 1H), 3.80 (t, J = 6.3 Hz, 2H), 2.55 (qd, J = 6.2, 1.3 Hz, 2H), 1.58 (s, 1H); 13 26 (2-Vinylphenyl)methanol (2j). Prepared according to General Procedure A, corresponding N-alkoxypyridinium salt 1j (0.1 mmol) was employed.…”

Efficient and Straightforward Syntheses of Two United States Pharmacopeia Sitagliptin Impurities: 3-Desamino-2,3-dehydrositagliptin and 3-Desamino-3,4-dehydrositagliptin

“…Our first attempt to develop a synthetic route to alkene impurity 10 from methyl ( E )-4-(2,4,5-trifluorophenyl)­but-2-enoate ( 12 ) was to perform regio-isomerization of allylbenzene intermediate 12 to the regio-isomerized product 13 (Scheme ). Previous studies have indicated that bases, such as NH 3 , LiO t Bu, LiHMDS, K 2 CO 3 , , KF, − KOH, and KO t Bu, , can promote the regio-isomerization of the allylbenzene derivative. Accordingly, the conversion of 12 to 13 in the presence of different bases (NaH, Et 3 N, NMM, and DBU) was monitored by NMR (see the Supporting Information, Table S1).…”