2-Methoxybenzaldehyde → 1-Cyclopentylidenemethyl-2-methoxybenzene

Participants

Reaction Conditions

Reaction Steps

A suspension of sodium hydride (608 mmol, 24.3 g; 60% dispersion in oil) in dry DMSO (3L) was heated to 60° C. for one hour and cooled to an internal temperature of 42° C. Cyclopentyltriphenylphosphonium bromide (608 mmol, 250 g) was added in one portion and to the resulting red solution was added 2-methoxybenzaldehyde (669 mmol, 91.0 g; 80.7 mL) dropwise over a few minutes. The dark reaction mixture was heated to 60° C. for 18 hours and cooled to room temperature. The reaction was diluted with water (4L), extracted with CH2Cl2 (2×3L) and concentrated in vacuo. The residue was partitioned between 15:1 hexane/EtOAc (1.3L) and water (1.6L), the organics washed with water (3×600 mL), dried (Na2SO4) and concentrated in vacuo. Upon concentration, triphenylphosphine oxide crystallized out of solution. The suspension was diluted with hexane, the solids removed by filtration, and the filtrate concentrated in vacuo to afford a dark oil. This material was vacuum distilled to afford the title compound as a light yellow oil (76.7 g, 67%). The desired material comes over at 90°-97° C. at 0.05 mm Hg and is used as such in the subsequent transformation.

Provenance & Evidence