Photo-Catalytic (Molander) Alkylation Screening Kit

The trifluoroborate alkylation reaction (Minisci reaction) described by Prof. Molander is a powerful late stage functionalization tool.

Photo-catalytic alkylation screen kit using 4 photocatalysts
and 8 different alkylation reagents
in 5 µmol scale reaction condition.

The typical protocol is performed at 0.1 mol/l of substrate prepared as solution in DMSO or H₂O/ACN with 5 equiv. of trifluoroacetic acid. Each sealed reaction vial contains either 7.5 µmol of BF₃K reagent with 10 µmol of K₂S₂O₈ or 25 µmol of tert-butyl peracetate. Typically, the reaction is performed with 6200K white LED or blue LED (450 nm). The alkylation screen kit contains 4 sets of vials allowing the screening of four catalysts. Sparging reaction solvents with nitrogen or argon while transferring reagents is important to achieve highest conversions of product.

Protocol at 50 µl volume reaction condition

• In the substrate solution vial provided, prepare 1.6 ml of substrate solution at 0.1 mol/L of substrate (160 µmol substrate needed) in either DMSO or H₂O/ACN with 61.2 µL of trifluoroacetic acid (5 equiv.).  Mix thoroughly.
  Transfer 400 µmol of solution to each catalyst vial.  Vortex thoroughly.
• Degas the first substrate/catalyst solution with subsurface sparging via N₂ or Ar line with exit needle for 5 minutes.
• Using a clean and dry syringe, add 50 µL of the substrate solution to each reaction vial (8 reactions).
  Place samples in vial holder HCK-1006-01-017.
• Repeat steps 3 through 5 for each catalyst solution.
• Turn on lamp (6200K white LED or blue LED 450 nm) and stir vials for 12 to 18 hours (or longer if necessary and there is substrate remaining).  Be sure to plug in fan to maintain RT.
• Upon completion of reaction, prepare analytical sample for each reaction condition with 5 µl sample diluted into 200 µl in either DMSO or water/acetonitrile 50/50.
• Analyze resulting analytical samples by LC/MS.