CID 406 → Lithium diisopropylamide

Participants

Reaction Conditions

Reaction Steps

11.42 g (30.51 moles) of the phosphonate obtained in EXAMPLE II(b) are dissolved in 50 ml of THF. This solution is then cooled to -78° C. and there is slowly added thereto a solution of lithium di-isopropylamide which was prepared in a conventional manner starting with 3.4 g (33.58 mmoles) of di-isopropylamine and 2.1 ml (33.56 mmole) of a solution of N-butyllithium (1.6M in hexane). The red-orange solution thus obtained is stirred for 30 minutes at -78° C. and a suspension of 3-(1-adamantyl)-4-methoxybenzaldehyde obtained above in part (a) (7.5 g 27.74 moles) in 140 ml of THF is added in fractions thereto. This addition lasts for about 10 minutes. The reaction mixture is then stirred initially for 20 minutes at -78° C. and then for 2 hours at 25° C. The mixture is poured into water and extracted three times with 100ml ethylether. The organic phase is washed with a saturated solution of sodium chloride, dried over magnesium sulfate, filtered and the solvents evaporated. The residue in chromatographed on a silica column, as in Example II(c), yielding a mixture of two isomers, E and Z, of the methyl ester of p-[1-(2,2-dimethoxyethyl)-2-[3-(1-adamantyl)-4methoxyphenyl]-vinyl]benzoic acid (7.5 g, 53% yield) in the form of a partially crystallized light yellow oil. This mixture is used as such in the continuation of the synthesis.

Provenance & Evidence