Hydrochloric Acid → Z-2,2-dimethyl-5-carboxymethylene-1,3-dioxolan-4-one

Participants

Reaction Conditions

Reaction Steps

A solution of tartaric acid bis(acetonide) prepared as in Example 1 (1.84 g, 8.0 mmol) in anhydrous tetrahydrofuran (15 mL) was cooled to −40° C. A 1 M solution of potassium tert-butoxide in tetrahydrofuran (8.0 mL, 8 mmol) was added by syringe over the course of 5 min. The mixture was stirred an additional 20 min. at −40° C. after which 4 M HCl in dioxane (3.0 mL, 12 mmol) was added and the reaction was allowed to warm. Ethyl acetate (75 mL) and 1 N HCl (25 mL) were added. The organic layer was separated and washed with water (25 mL). Removal of volatiles on the rotary evaporator afforded the crude product (1.37 g, 99%). This material contained ca. 5% of a side-product presumed to be the E-stereoisomer and characterized by an NMR singlet at δ 5.48 as well as ca. 10% of recovered bis(acetonide) starting material. A 0.63 g sample of this material was crystallized from hot ethyl acetate to afford Z-2,2-dimethyl-5-carboxymethylene-1,3-dioxolan-4-one as fine white needles (0.37 g).

Provenance & Evidence