7. 环化反应解析
反应通式:
O H3C S CH or H3C S CH2 2 H3C H3C X X R' R' R'
+
ቤተ መጻሕፍቲ ባይዱ
R'
X= O, CH2, NR, S, CHCOR, CHCO2R, CHCONR2, CHCN
Chem. Commun. 2003, 2644-2651.
反应机理:
O H3C S CH 2 R' H3C O O R'' O C R' R' H3C S+ CH2 H3C
反应机理1:
H O O O H -H
+
H H+
O+
O O
-H
+
O
H O H R H O O+ H O+ O O
O+
H O O
O
O H O
H H
+
R
OH
O
O O
-H+ O NH2 O O R
R H O
OH O O H+
R H
OH2 O+
+
-H2O
R
O O -H
+
H 2N HN O HN
H2 N O NH
Org. Lett. 2000, 2, 3761–3764.
(Hetero) Diels-Alder Reaction
——重要的环化反应
(见加成反应一章相关内容)
Biginelli (比吉内利)反应
反应通式:
It was developed by Pietro Biginelli in 1891. It can be cat. by Brø nsted or Lewis acids such as BF3. The products dihydropyrimidinones are widely used in the pharmaceutical industry as antihypertensive agents and calcium channel blockers.
-
O R'
+
R' O
H3C S H3C
The original publication by Johnson in 1961 concerned the reaction of 9-dimethylsulfonium fluorenylide with PhCHO.
J. Am. Chem. Soc. 1961, 83, 417-423.
Dimethyloxosulfonium methylide, (CH3)2SOCH2, is known as the Corey-Chaykovsky reagent, or CCR for short.
第7章 环化反应
1. Bergman (伯格曼)环化 2. (Hetero)Diels-Alder 反应(见第6章) 3. Biginelli (比吉内利)反应 4. Corey-Chaykovsky 反应 (硫ylide的反应) 5. Darzens 反应 (合成环氧) 6. Bischler-Napieralski 比施勒-涅皮拉斯基反应 7. Doebner (多布纳)反应 (合成喹啉-4-羧酸) 8. Doebner-Miller 反应 (合成喹啉) 9. Friedlander 喹啉合成法 10. Feist-Benary 呋喃合成法 11. Fischer 吲哚合成法 12. Robinson-Gabriel 噁唑合成法 13. Gewald 反应 (合成2-氨基噻吩) 14. Hantzsch (汉栖)吡啶合成法 15. Hantzsch (汉栖)吡咯合成法 16. Huisgen 环加成 (合成三唑)
When quenched by CCl4 the product is 1,4-dichlorobenzene;
and with MeOH the product is BnOH.
反应机理:
反应实例:
J. Org. Chem., 1998, 63, 8229–8234.
O OCH3 N H3CO N H3CO OH OCH3 N H3CO N or hγ H3CO N N N N OCH3 OH OCH3 O
10 mol % Cat. R1CHO CH2Cl2, 25℃
HN X
NH
*
R1
X= O, S
yield: up to 94% up to 97 % ee Cat.
O O O P OH
J. Am. Chem. Soc. 2006, 128, 14802–14803.
Corey-Chaykovsky Reaction
许申鸿,Biginelli 反应介绍, 大学化学, 2004, 19, 27.
N H2N O
N NH2Cl
O
O
R'
O
O
R'
+
CO2R'
R CHO
R HN
N
R HN NH
NH2Cl
N N
J. Org. Chem. 2006, 71, 7706-7714.
X H2N O NH2 O
CO2R2
+
OR2
O H+ -H2O Ph O H2N N+ H NH Ph NH2
H O NH2
C. O. Kappe, J. Org. Chem. 1997, 62, 7201–7204.
近期研究:
最大优点是三种原料一锅煮,操作简单; 其缺点是收率太低(20-50%)。 1993年,奥地利格拉茨大学C. Oliver Kappe教授发表了一 篇综述(Tetrahedron 1993, 49, 6937-6963),2000年,又发表了一篇综 述(Acc. Chem. Res. 2000, 33, 879-888),该反应才得到了广泛关注, 开始从反应底物的设计、催化剂选择、反应条件的选择等途径 去提高反应收率。
H2 N O N H R
R
-H2O
F. Sweet, J. D. Fissekis,J. Am. Chem. Soc. 1973, 95, 8737.
反应机理2:
O PhCHO H2N NH2 Ph O Ph N H OH+ CO2Et -H2O HN O HN Ph
CO2Et
OH NH
O NH2 O O
Bergman 伯格曼环化
反应通式:
or hγ
The Bergman cyclization is named for the American chemist Robert George Bergman. The reaction proceeds by a thermal reaction or pyrolysis ( > 200 º C).