title: Merging asymmetric Henry reaction with organocatalytic cascade reaction for the construction of a chiral indolizidine alkaloid skeleton.
abstract: A sequential reaction combining the copper-catalyzed asymmetric Henry reaction with the organocatalytic Michael addition-hemiacetalization cascade reaction was developed. The C1-symmetric chiral diamine L1-copper complex was responsible for the first highly enantioselective Henry reaction, while diphenylprolinol silyl ether A acted as effective organocatalyst for the second cascade reaction between chiral β-nitro alcohol and α,β-unsaturated aldehydes. Via rational design and combination of the two independent catalytic systems, good yields and excellent enantioselectivities and diastereoselectivities were achieved for a broad substrate scope under mild reaction conditions. The synthetic utility of this sequential catalytic asymmetric cascade reaction was demonstrated as an alternative and straightforward stereoselective synthesis strategy for chiral indolizidine alkaloid and its analogues.
authors.affiliation: Key Laboratory of Small Fuctional Organic Molecule, Ministry of Education, Jiangxi Normal University , 99 Ziyang Road, Nanchang, Jiangxi 330022, China.
authors.forename: Yirong
authors.initials: Y
authors.lastname: Zhou
authors.forename: Qin
authors.initials: Q
authors.lastname: Yang
authors.forename: Jian
authors.initials: J
authors.lastname: Shen
authors.forename: Xin
authors.initials: X
authors.lastname: Chen
authors.forename: Yiyuan
authors.initials: Y
authors.lastname: Peng
authors.forename: Yuefa
authors.initials: Y
authors.lastname: Gong
mesh_terms: D000447:Aldehydes; D000470:Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry*; D002384:Catalysis; D003300:Copper / Q000737:chemistry*; D004987:Ethers / Q000737:chemistry*; D054836:Indolizidines / Q000138:chemical synthesis* / Q000737:chemistry*; D015394:Molecular Structure; D011392:Proline / Q000031:analogs & derivatives* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000447:Aldehydes; D000470:Alkaloids; D004987:Ethers; D054836:Indolizidines; C529940:diphenylprolinol silyl ether; D003300:Copper; D011392:Proline