Cyanomethylenetributylphosphorane

Synthesis

At 0 °C, a solution of 27.0 g (97.6 mmol) of ST913 in 100 mL of anhydrous tetrahydrofuran was added together with a solution of 44.4 mL (97.6 mmol) of 2,2 N-butyllithium in hexane. After stirring at room temperature for 1 hour, the reaction mixture was evaporated, and the residue was dissolved in toluene petroleum ether. The precipitated lithium chloride was filtered off, and the res solution was evaporated. The residue was purified by short-path distillation under high vacuum (220–230 °C/0.1 mbar). 15.3 g of cyanomethylenetri-n-butylphosphine (65% of the theoretical value) was given as a colorless liquid.

Figure: Synthetic Route of CYANOMETHYLENETRIBUTYLPHOSPHORANE

Uses

(Tributylphosphoranylidene)acetonitrile can be utilized as a reagent in the:

• Stereoselective synthesis of skytanthine and other O- and N-containing heterocycles by Mitsunobu intramolecular cycloalkylation.
• Wittig olefination of esters, lactones, N-Boc lactam, and cyclic imide to corresponding Wittig products.

General Description

(Tributylphosphoranylidene)acetonitrile is a stabilized trialkylphosphorane that can act as a substitute to the diethyl azodicarboxylate and triphenylphosphine (DEAD-TPP) system for Mitsunobu reaction between nucleophiles (HA) and alcohols (ROH) to form RA. It is highly useful when the pKa of the nucleophiles are higher than 11.