Tetrahydrofuran → Tert.-butyl(1R,cis)2,2-dimethyl-3-(carboxy ethynyl)cyclopropane-carboxylate

Participants

Reaction Conditions

Reaction Steps

60 ml of a 20% solution of butyllithium in cyclohexane were added at -65° C. to a mixture of 26 g of tert.-butyl (1R, cis) 2,2-dimethyl-3-(2,2-dibromovinyl)-cyclopropane-carboxylate and 175 ml of anhydrous tetrahydrofuran and the mixture was stirred at -60° C. for one hour. A current of carbon dioxide was bubbled through the mixture for 90 minutes and the mixture was poured into an ice-water mixture containing N sodium hydroxide. The alkaline aqueous phase was acidified to a pH of 4 and was extracted with ether. The organic phase was dried and evaporated to dryness under reduced pressure. The residue was crystallized from petroleum ether (b.p.=60°-80° C. to obtain 8.3 g of tert.-butyl (1R,cis) 2,2-dimethyl-3-(3-hydroxy-3-oxo-1-propynyl)-cyclopropane-1-carboxylate melting at 144° C.

Provenance & Evidence