تفاعل #742260

معادلة التفاعل

(E)-3-[2-(tert-Butyl-dimethyl-silanoxy)-phenyl]-acrylic acid

1-tert-butyl-4-(3-ethoxy-2-methyl-allyl)-benzene

3-(4-tert-butyl-phenyl)-2-methyl-propionaldehyde

→

ester

المردود 28.2%

(E)-3(2-Hydroxy-phenyl)-acrylic acid 3(4-tert-butyl-phenyl)-1-ethoxy-propyl ester

المردود 28.2%

المذيبات

THF

toluene

ظروف التفاعل

المعالجة

1. 1
   أخرىThe reaction mixture was partitioned between saturated sodium carbonate and hexane
2. 2
   غسيلthe organic layer was washed with brine
3. 3
   تجفيفdried over (Na2SO4)
4. 4
   أخرىevaporated to dryness
5. 5
   أخرىto yield 5.3 g of the crude intermediate (E)-3-[2-(tert-Butyl-dimethyl-silanoxy)-phenyl]-acrylic acid 3-(4-tert-butyl-phenyl)-1-ethoxy-propyl ester as a pale yellow oil
6. 6
   تركيزthe mixture was concentrated
7. 7
   أخرىpurification by repeated flash chromatography

الإجراء التجريبي

A solution of 3.1 g of (E)-3-[2-(tert-Butyl-dimethyl-silanoxy)-phenyl]-acrylic acid, 3.0 g of 1-tert-butyl-4-(3-ethoxy-2-methyl-allyl)-benzene, accessible from 3-(4-tert-butyl-phenyl)-2-methyl-propionaldehyde via a two step procedure according to P. D. Bartlett and A A. Frimer, Heterocycles 11, 419-435, (1978), and 20 mg of p-TSA in 25 ml of toluene was stirred at 0° C. for 4 h and at room temperature for 14 h. The reaction mixture was partitioned between saturated sodium carbonate and hexane and the organic layer was washed with brine, dried over (Na2SO4) and evaporated to dryness to yield 5.3 g of the crude intermediate (E)-3-[2-(tert-Butyl-dimethyl-silanoxy)-phenyl]-acrylic acid 3-(4-tert-butyl-phenyl)-1-ethoxy-propyl ester as a pale yellow oil. This was dissolved in 20 ml of THF and treated at 0° C. with 3.2 g of solid TBAF-3H2O. After 30 min., the mixture was concentrated and purification by repeated flash chromatography yielded 1.2 g of the title ester (a mixture of diastereoisomers) as a pale yellow oil.

المصدر