Pyridine, 4-[(1E)-2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)ethenyl]- synthesis

Yield:1015243-13-6 70%

Reaction Conditions:

with tris(1,5-diphenylpenta-1,4-dien-3-one)dipalladium;N-ethyl-N,N-diisopropylamine;tri-tert-butylphosphonium hydrogen tetrafluoroborate in toluene at 20 - 85; for 15 h;Inert atmosphere;Time;

Steps:

242.1; 278.1 Step 1 : (E)-4-( 2-( 4, 4, 5, 5-Tetramethyl-l, 3, 2-dioxaborolan-2-yl)vinyl)pyridine

A mixture of 4-bromopyridine (3 g, 18.99 mmol), 4, 4,5, 5-tetramethyl-2 -vinyl-1, 3,2- dioxaborolane (3.51 g, 22.79 mmol, 3.86 mL), tri-/c/7-butylphosphanium tetrafluoroborate (550.89 mg, 1.90 mmol), Pd₂(dba)₃ (869.37 mg, 949.39 umol) and DIEA (4.91 g, 37.98 mmol, 6.61 mL) in toluene (15 mL) was degassed and purged with N2 (3x) at 20 °C. The mixture was then stirred at 85 °C for 15 hrs under an N2 atmosphere. The mixture was concentrated to give a residue that was purified by silica gel column chromatography using a 0-26% EtOAc/petroleum ether gradient eluent to afford the title compound (3.1 g, 70%) as a yellow solid. 'H NMR (400 MHz, CDCh) 8 8.61 (br d, J=5.01 Hz, 2 H), 7.34 (d, J=6.36 Hz, 2 H), 7.28 (d, J=7.21 Hz, 1 H), 6.39 (d, J=18.34 Hz, 1 H), 1.33 (s, 12 H). MS-ESI (m/z) calc’d for C13H19BNO₂ [M+H]⁺: 232.1. Found 232.3.

References:

WO2022/155419,2022,A1 Location in patent:Page/Page column 437-438; 504-505