title: Effective and novel enantioselective preparation of pyranopyrazoles and pyranocoumarins that is catalyzed by a quinine-derived primary amine.
abstract: In this study, we executed an effective and novel enantioselective Michael/cyclodehydration sequential reaction between pyrazolin-5-one (or 4-hydroxy-2-pyrone) and chalcones that is catalyzed by a quinine-derived primary amine L7 in the presence of Boc-D-Phg-OH. Chiral pyranopyrazoles and pyranocoumarins were obtained in excellent enantioselectivities (up to 93%) with moderate yields and moderate enantioselectivities with high yields (up to 84%).
authors.affiliation: College of Pharmacy and Yonsei Institute of Pharmaceutical Sciences, Yonsei University, 85 Songdogwahak-ro, Yeonsu-gu, Incheon 406-840, Republic of Korea. organicjeong@yonsei.ac.kr.
authors.forename: Sai
authors.initials: S
authors.lastname: Yang
authors.forename: Liu-Lan
authors.initials: LL
authors.lastname: Shen
authors.forename: Yoon-Jung
authors.initials: YJ
authors.lastname: Kim
authors.forename: Jin-Hyun
authors.initials: JH
authors.lastname: Jeong
mesh_terms: D000588:Amines / Q000737:chemistry*; D002384:Catalysis; D003374:Coumarins / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D011714:Pyrans / Q000138:chemical synthesis* / Q000737:chemistry; D011720:Pyrazoles / Q000138:chemical synthesis* / Q000737:chemistry; D011803:Quinine / Q000031:analogs & derivatives / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000588:Amines; D003374:Coumarins; D011714:Pyrans; D011720:Pyrazoles; D011803:Quinine