title: Stereoregulations of pyrimidinone based chiral auxiliary in aldol and alkylation reactions: a convenient route to oxyneolignans.
abstract: (S)-4-Isopropyl-1-phenyltetrahydropyrimidin-2(1H)-one was synthesized and evaluated as a chiral auxiliary for asymmetric acetate and propionate aldol reactions, by generation of titanium and lithium enolates, affording excellent yields and stereoselectivities for syn and anti aldol diastereomers, respectively. High stereoselectivities were also obtained in lithium mediated alkylation reactions. The application of the auxiliary was exemplified in the asymmetric synthesis of a natural oxyneolignan, (+)-(7S,8S)-4-hydroxy-3,3',5'-trimethoxy-8',9'-dinor-8,4'-oxyneoligna-7,9-diol-7'-oic acid.
authors.affiliation: Department of Medicinal Chemistry, National Institute of Pharmaceutical Education and Research, Sector 67, Mohali, Punjab 160062, India.
authors.forename: Mangilal
authors.initials: M
authors.lastname: Chouhan
authors.forename: Ratnesh
authors.initials: R
authors.lastname: Sharma
authors.forename: Vipin A
authors.initials: VA
authors.lastname: Nair
mesh_terms: D000438:Alcohols; D000447:Aldehydes / Q000737:chemistry; D000478:Alkylation; D002264:Carboxylic Acids; D017705:Lignans / Q000138:chemical synthesis* / Q000737:chemistry; D011422:Propionates; D011744:Pyrimidinones / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: C579609:(S)-4-isopropyl-1-phenyltetrahydropyrimidin-2(1H)-one; D000438:Alcohols; D000447:Aldehydes; D002264:Carboxylic Acids; D017705:Lignans; D011422:Propionates; D011744:Pyrimidinones; C116609:3-hydroxybutanal