All Notebooks | Help | Support | About
3rd October 2013 @ 08:00

See also: Synthesis of N-methyl-3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzenesulfonamide (AEW 69-1) and Synthesis of Boronic Acid Pinacol Ester - MNR103-1 

Procedure

AEW 89-1 (~0.98 mmol, 1 equiv.), potassium acetate (380 mg, 3.92 mmol, 4 equiv.) and bis(pinacolatodiborane) (370 mg, 1.47 mmol, 1.5 equiv.) were dissolved in anhydrous 1,4-dioxane (5 mL). Argon was bubbled through the suspension for ten minutes before [1,1-Bis(diphenylphosphino)ferrocene]dichloropalladium(II) (40 mg, 0.05 mmol, 0.05 equiv.) was added and the suspension heated at reflux with stirring overnight. 

In the morning - the reaction couldn't contain itself with excitement - might have lost some product:

Reaction mixture allowed to cool and then filtered through a pad of Celite and washed with EtOAc and MeOH to give a black mixture. 1H NMR indicates complete transformation to a compound consistent with the desired product. Crude mixture was purified by flash column chromatography over silica (EtOAc/Hexane, 50:50) to give two fractions (need to choose slower gradient next time). Repurified to give 217 mg, 0.7 mmol, 71% yield) of the pure product.

m.p. 1H NMR (300 MHz, CDCl3): ;  13C NMR (75 MHz, CDCl3) δ: ;  IR νmax (neat) /cm-1 HRMS (ESI+) found xxx [M+H]+, xxxx requires xxx.

 

TLC

(EtOAc/Hex, 50:50) visualised with vanillin - light green spot, very hard to see SM in UV.

AEW 91-1 (50-50, EtOAc:Hex).jpg

Data:

Crude NMR:

 

Pure Product:

 

Raw Data:

 

Hazard and Risk Assessment:

See: Synthesis of Boronic Acid Pinacol Ester - MNR103-1


InChi String:

InChI=1S/C8H10BrNO2S/c1-10(2)13(11,12)8-5-3-4-7(9)6-8/h3-6H,1-2H3

and

InChI=1S/C12H24B2O4/c1-9(2)10(3,4)16-13(15-9)14-17-11(5,6)12(7,8)18-14/h1-8H3

gives

InChI=1S/C14H22BNO4S/c1-13(2)14(3,4)20-15(19-13)11-8-7-9-12(10-11)21(17,18)16(5)6/h7-10H,1-6H3

Linked Posts
Attached Files
AEW 91-1.cdx
AEW 91-1.png
AEW 91-1 explosion.jpg
AEW 91-1 (50-50, EtOAc:Hex).jpg