Reaction #6609

Reaction equation

ethyl chloroformate

4-carboxybenzyl 5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthyl ether

triethylamine

sodium borohydride

hydrochloric acid

→

title compound

Yield 37.7%

4-Hydroxymethylbenzyl 5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthyl ether

Yield 37.7%

Solvents

tetrahydrofuran

tetrahydrofuran

tetrahydrofuran

water

Conditions

Workup

1. 1
   Filtrationthe solid was filtered off
2. 2
   workup.WAITto reach room temperature within 1 h
3. 3
   OtherMost of the tetrahydrofuran was removed in a rotary evaporator
4. 4
   Extractionthe remaining aqueous phase was extracted with chloroform
5. 5
   DryingThe organic phase was dried over Na2SO4
6. 6
   Concentrationconcentrated
7. 7
   OtherFractional crystallization from ethyl acetate

Procedure

A solution of 0.97 g (9 mmol) of ethyl chloroformate in 5 ml of tetrahydrofuran was added dropwise to a solution of 3 g (9 mmol) of 4-carboxybenzyl 5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthyl ether and 0.9 g (9 mmol) of triethylamine in 20 ml of dry tetrahydrofuran at 0° C. The mixture was stirred at 0° C for 30 min, the solid was filtered off, and the filtrate was added dropwise to a solution of 0.83 g (22 mmol) of sodium borohydride in 8 ml of tetrahydrofuran and 8 ml of water. The reaction mixture was then allowed to reach room temperature within 1 h and was then acidified with 1N hydrochloric acid. Most of the tetrahydrofuran was removed in a rotary evaporator, and the remaining aqueous phase was extracted with chloroform. The organic phase was dried over Na2SO4 and concentrated. Fractional crystallization from ethyl acetate, discarding the first fraction, resulted in 1.1 g of the title compound of melting point 108°-109° C.

Source