Malonates reaction with benzyl ether

One of the limitations of the copper- and indium-catalyzed oxidative alkylation protocol is the use of a relatively reactive malonate. Li found that simple ketones 16 can undergo oxidative alkylation reactions with benzyl ethers 36 by using DDQ as an oxidant at high temperatures (Scheme 23) [40]. 

The reaction of the pyrazoles (348) with diethyl malonate gives derivatives (349) (Scheme 31) <73G >05, 78JOC4154). Similarly condensation with benzyl cyanide in 2-hydroxydiethyl ether gives... 

Dibenzyl malonate (124.5 g, 0.44 mol) was taken up in dry DMF and potassium t-butoxide (49.2 g, 0.44 mol) was added portionwise with stirring and cooling. When a homogeneous solution had formed it was cooled to 0°C, then t-butyl-2R-bromo-5-methylpentanoate (110.1 g, 0.44 mol) in DMF (200 ml) was added dropwise over 1 h. When addition was complete the reaction was transfered to a cold room at 5°C and left for 4 days. The reaction mixture was partitioned between ethyl acetate and saturated ammonium chloride then the aqueous layer extracted with further ethyl acetate (4 x 500 ml), drying and solvent removal left an oil (228.0 g) heavily contaminated with DMF. This oil was taken into ether (1 L) and washed with brine (2 x 11) then the organic layer dried (magnesium sulfate), solvent removed under reduced pressure to leave the benzyl (2-benzyloxycarbonyl-3R-(t-butoxycarbonyl)-5-methylhexanoate (179.0 g) contaminated with a small amount of dibenzyl malonate. 

The sodium salt of malonate carbanions reacts quantitatively with the living ends of poly(vinyl ether) s to give a stable carbon-carbon bond. This reaction was used to functionalize the ends of Hving poly(isobutyl vinyl ether) or poly(benzyl vinyl ether) with a vinyl ether polymerizable end group supported by a malonate ion (end-capping agent, 7) [151]. 

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