Tetrahedron p. 4951 - 4994 (1990)
Update date:2022-09-26
Topics:
Romo, Daniel
Romine, Jeffrey L.
Midura, Wanda
Meyers
A novel diastereoselective cyclopropanation based on readily available chiral bicylic lactams (1b-c, 6a-b) has provided a number of enantiomerically pure cyclopropanes. Cyclopropanations of unsaturated lactams (10a-h, 12-14) were performed using sulfur ylides as well as a 3+2 cycloaddition-photolysis sequence and furnished the desired cyclopropane adducts (16, 17, 19, 22) in fair to excellent yields. In all cases involving sulfur ylides, cyclopropanations proceeded with a high degree of exo/endo diastereoselectivity (>;90%). However, the mode of addition, exo vs endo, was found to be highly dependent on the angular substituent of the unsaturated lactam. In the case of diazoalkane cycloadditions, high regioselectivity was observed in all cases although exo/endo selectivity was governed by the diazoalkane employed. Diazoisopropane, being more reactive than diazomethane, normally led to lower diastereomeric ratios. Minor diastereomers could be readily removed by chromatography or in most cases by a single recrystallization to provide diastereomerically pure cyclopropyl bicyclic lactams (16, 17, 19, 22). Applications of this methodology to compounds of biological significance was exemplified by an asymmetric, total synthesis of cis-(1S, 3R)-deltamethrinic acid (34) and R-(-)- dictyopterene C′ (42) in high enantiomeric purity.
View MoreShenZhen InnoSyn Biotech Co.,Ltd
website:http://www.innosyns.com
Contact:+86-755-28351685
Address:Floor 5 & 6, Building A1, HAIKEXING Strategic Innovative Industrial Park, 16 BaoShan Road, PingShan District
Longhui qunfeng Chemical Co., Ltd
Contact:86-731-82173407
Address:South-east Industrial Park, Longhui County, Hunan Province, China
KangZhiYuan Pharmaceutical Company Limited
Contact:(Sabrina)86-20-85273232
Address:4th floor, building B, Dadi industry zone, Tangxia, Tianhe, Guangzhou, China
jiangsu senxuan pharmaceutical and chemical co.,ltd
Contact:86-523-87982810
Address:hongqiao industrial zone,taixing,jiangsu china
Wuxi Pharma-Trading Import & Export Co.,Ltd.
Contact:+86-510-82304590 82716390
Address:Room 523,Youzu Alliance Building,No.88 Renmin Zhonglu,Wuxi,Jiangsu,China
Doi:10.1021/jo00271a043
(1989)Doi:10.1039/c3dt51800k
(2013)Doi:10.1016/j.jfluchem.2020.109516
(2020)Doi:10.1007/BF01435798
(1996)Doi:10.1021/jo00220a019
(1985)Doi:10.1021/ja961640y
(1996)