Double tip needles

Re(CO)sBr,5 and 2.5 g (38 mmol) of zinc dust. The flask is then capped with a rubber serum stopper and evacuated. Into another Schlenk flask is placed 50 mL of 2,5,8,22,14-pentaoxapentadecane (tetraglyme, Aldrich) and 4 m L of 85% phopshoric acid. This flask is also capped with a serum stopper and the solution is degassed in vacuo for 2 h at room temperature. At this point the acid solution is transferred under nitrogen to the flask containing the solids via a double-tipped needle (cannula). The flask is wrapped with aluminum foil for protection from light, and the mixture is stirred under nitrogen until no solid Re(CO)sBr remains. This should take 24 h. 

The submitters used a 50% solution of l-buten-3-yne in xylene, available from Chemical Samples Company. For transferring this solution, the following procedure may be recommended. An ampule containing the solution is cooled with an ice-salt bath, opened, and capped with a rubber septum. A weighed measuring flask capped with a rubber septum is cooled with the ice-salt bath. To this is introduced the cooled solution by means of a double-tipped needle, and the weighed solution is then introduced to the reaction flask by means of a double-tipped needle. 

Dry the three-necked, round-bottomed flask with magnetic stirring bar and double-tipped needle overnight in an electric oven at 110°C. Allow to cool in a desiccator before use. 

Cannula techniques air-sensitive materials, 7 components, 6 double tip needles, 9 flexibility, 7 solution transfer, 6-23 speed,7... 

Diphenylzirconocene Cp2ZrPh2 (0.375 g, 1 mmol) was placed in the tube with a magnetic stirrer bar, under argon. Toluene (5 mL) was added followed by addition via a double-tipped needle of a solution of phospholene l(Rp) or l(Sp) (0.162 g, 1 mmol) in 3 mL of toluene at room temperature. The resulting mixture was heated at 80 °C for 6 hours, then cooled to 20 °C. This solution contains the 8,8 dicyclopentadienyl-l-phenyl-l,2,3,3a,8,8a-hexahydro-l-phos-pha-8-zircona-cyclopenta[a]inden 2(RP) or 2(SP) which were used as prepared. 

Dimethylphenyl isocyanide (0.132 g, 1 mmol) in solution in 3 mL of toluene was added via a double tipped needle to the solution prepared above and stirred overnight at room temperature. Solvents were evaporated to dryness and the solid residue was extracted with pentane (3 x 50 mL) and filtered on Celite 5 g. Enantiopure ligands 1(RP) or 1(SP) were obtained as yellow solids in 72% yield (0.276 g) after solvent removal. 

---