(1R,2R)-1,2-dibromocyclohexane

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Within 2 hours, 1.1 l of ethanol was added dropwise to 69 g of finely chopped sodium in a 2-liter three-necked flask equipped with dropping funnel, reflux condenser, and agitator. The hot alcoholate solution was combined dropwise--again within 2 hours--with 196 g of diethyl malonate. After allowing the reaction mixture to cool, 296 g of trans-1,2-dibromocyclohexane was added--within 2 hours--to the reaction solution, which latter was then boiled under reflux overnight. After concentration of the reaction solution on a forced circulation evaporator, the residue was combined with ether and dilute hydrochloric acid, the organic phase then washed with saturated sodium chloride solution, concentrated, and distilled under vacuum, thus obtaining 197 g, bp1 119°-121° C. equipped reflux condenser again within 2 hours to cool within 2 hours under reflux overnight After concentration of the reaction solution on a forced circulation evaporator the organic phase then washed with saturated sodium chloride solution concentrated distilled under vacuum thus obtaining 197 g, bp1 119°-121° C.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Within 2 hours, 1.1 l of ethanol was added dropwise to 69 g of finely chopped sodium in a 2-liter three-necked flask equipped with dropping funnel, reflux condenser, and agitator. The hot alcoholate solution was combined dropwise--again within 2 hours--with 196 g of diethyl malonate. After allowing the reaction mixture to cool, 296 g of trans-1,2-dibromocyclohexane was added--within 2 hours--to the reaction solution, which latter was then boiled under reflux overnight. After concentration of the reaction solution on a forced circulation evaporator, the residue was combined with ether and dilute hydrochloric acid, the organic phase then washed with saturated sodium chloride solution, concentrated, and distilled under vacuum, thus obtaining 197 g, bp1 119°-121° C. equipped reflux condenser again within 2 hours to cool within 2 hours under reflux overnight After concentration of the reaction solution on a forced circulation evaporator the organic phase then washed with saturated sodium chloride solution concentrated distilled under vacuum thus obtaining 197 g, bp1 119°-121° C.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Within 2 hours, 1.1 l of ethanol was added dropwise to 69 g of finely chopped sodium in a 2-liter three-necked flask equipped with dropping funnel, reflux condenser, and agitator. The hot alcoholate solution was combined dropwise--again within 2 hours--with 196 g of diethyl malonate. After allowing the reaction mixture to cool, 296 g of trans-1,2-dibromocyclohexane was added--within 2 hours--to the reaction solution, which latter was then boiled under reflux overnight. After concentration of the reaction solution on a forced circulation evaporator, the residue was combined with ether and dilute hydrochloric acid, the organic phase then washed with saturated sodium chloride solution, concentrated, and distilled under vacuum, thus obtaining 197 g, bp1 119°-121° C. equipped reflux condenser again within 2 hours to cool within 2 hours under reflux overnight After concentration of the reaction solution on a forced circulation evaporator the organic phase then washed with saturated sodium chloride solution concentrated distilled under vacuum thus obtaining 197 g, bp1 119°-121° C.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Within 2 hours, 1.1 l of ethanol was added dropwise to 69 g of finely chopped sodium in a 2-liter three-necked flask equipped with dropping funnel, reflux condenser, and agitator. The hot alcoholate solution was combined dropwise--again within 2 hours--with 196 g of diethyl malonate. After allowing the reaction mixture to cool, 296 g of trans-1,2-dibromocyclohexane was added--within 2 hours--to the reaction solution, which latter was then boiled under reflux overnight. After concentration of the reaction solution on a forced circulation evaporator, the residue was combined with ether and dilute hydrochloric acid, the organic phase then washed with saturated sodium chloride solution, concentrated, and distilled under vacuum, thus obtaining 197 g, bp1 119°-121° C. equipped reflux condenser again within 2 hours to cool within 2 hours under reflux overnight After concentration of the reaction solution on a forced circulation evaporator the organic phase then washed with saturated sodium chloride solution concentrated distilled under vacuum thus obtaining 197 g, bp1 119°-121° C.