Water → HCID 13366427, compound

Participants

Reaction Conditions

Reaction Steps

A suspension of 12.2 g (24 mmol) of (4-trifluoromethoxy-2,3,6-trimethylphenyl)methyltriphenylphosphonium chloride in 490 ml of dry THF was cooled to 45° C. and treated rapidly (over ~5 minutes) with 11.1 ml (25.5 mmol) of n-butyl lithium (2.3M in hexane) at -35° to -45° C. The reaction mixture was maintained at that temperature for 15 minutes, allowed to warm slowly to -25° C. at which time it became a slightly turbid orange solution. The mixture was cooled to -45° to -50° C. and 7.0 g (33 mmol) of ethyl-(2E,4E,6E)-3,7-dimethyl-8-oxo-octatrienoate in 50 ml of dry THF was added rapidly. The orange color disappeared; the reaction mixture was stirred at -25° C. for 2 hours, then allowed to warm to 0° C. over 1 hour and maintained at that temperature for 2 hours. The mixture was then poured into 1 liter of cold water and extracted with 250-ml portions of hexane. The organic phase was combined, washed successively with 500 ml of cold water, 2×500 ml of a 60% by volume methanol-water solution, and 500 ml of saturated NaCl solution, dried (MgSO4), filtered and concentrated. The resulting yellow oil was purified by HPLC (2 silica gel columns, 2% ethyl acetate in hexane as elutant) to give 5.79 g of ethyl-(2E,4E,6E,8E)-3,7-dimethyl-9-[2,3,6-trimethyl-4-(trifluoromethoxy)phenyl]-nonatetraenoate; mp 47°-49° C.

Provenance & Evidence