Réaction #74831

Équation de réaction

3-methoxycarbonylmethyl-2-methoxycarbonyl-2-(2-pentynyl)-cyclopentanol

3-methoxycarbonylmethyl-2-t-butoxycarbonyl-2-(2-pentynyl)-cyclopentanol

compound ( 1-a )

3-methoxycarbonylmethyl-2-t-butoxycarbonyl-2-(2-pentynyl)-cyclopentanol

hydrogen

→

compound ( 1-b )

2-tert-butoxycarbonyl-3-methoxycarbonylmethyl-2-(cis-2-pentenyl)-cyclopentanol

Solvants

n-hexane

acetone

Conditions de réaction

Traitement

1. 1
   Autreis thus reduced at room temperature
2. 2
   Autrehas absorbed the theoretical amount of the gas
3. 3
   Filtrationwhereupon the catalyst is filtered off
4. 4
   ConcentrationThe filtrate is concentrated in vacuo
5. 5
   workup.DISSOLUTIONthe residue dissolved in benzene-ethyl acetate
6. 6
   Autrepurified with a silica gel column
7. 7
   workup.DISTILLATIONThe product is distilled in a vacuum

Mode opératoire

A 1.4 g quantity of 3-methoxycarbonylmethyl-2-methoxycarbonyl-2-(2-pentynyl)-cyclopentanol (compound (1-a)) and 2.2 g of Lindlar catalyst are dissolved in a mixture of 50 ml of n-hexane and 5 ml of acetone. The starting compound is thus reduced at room temperature and atmospheric pressure with use of hydrogen gas. The reaction is completed when the solution has absorbed the theoretical amount of the gas, whereupon the catalyst is filtered off. The filtrate is concentrated in vacuo, and the residue dissolved in benzene-ethyl acetate and purified with a silica gel column. The product is distilled in a vacuum, giving 2-methoxycarbonyl-3-methoxycarbonylmethyl-2-(cis-2-pentenyl)-cyclopentanol (compound (1-b), R1 =R2 =CH3) in a yield of 87%, b.p. 74°-78° C./0.01 mm Hg.

Source