title: Diastereo- and enantioselective synthesis of nitroso Diels-Alder-type bicycloketones using dienamine: mechanistic insight into sequential nitroso Aldol/Michael reaction and application for optically pure 1-amino-3,4-diol synthesis.
abstract: This article presents complete diastereo- and highly enantioselective synthesis of nitroso Diels-Alder-type bicycloketones using dienamine. With the hydrogen bonding of two hydroxyls in the bulky binaphthol 1c, high enantioselectivities and complete diastereoselectivity are realized in 2-oxa-3-aza-bicycloketone synthesis. On the other hand, alpha,beta-unsaturated ketone can be employed as diene precursor, utilizing readily available tetrazole catalyst 3b, to provide the 3-oxa-2-aza-bicycloketones in moderate yields with complete enantioselectivities. Investigation into the reaction utilizing 2-morpholino-4,4-diphenylcyclohexadiene 2d clearly indicated that cyclization with the bulky binaphthol 1c is involved in the sequential process, the N-nitroso aldol reaction, followed by Michael addition. In addition, optically pure 1-amino-3,4-diol is synthesized from 2-oxa-3-aza-bicycloketones. Use of p-phenoxynitrosobenzene allows access to protected amino diol via cleavage of the N-Ph bond.
authors.affiliation: Department of Chemistry, University of Chicago, 5735 South Ellis Avenue, Chicago, Illinois 60637, USA.
authors.forename: Norie
authors.initials: N
authors.lastname: Momiyama
authors.forename: Yuhei
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Hisashi
authors.initials: H
authors.lastname: Yamamoto
mesh_terms: D000143:Acids / Q000737:chemistry; D000466:Alkadienes / Q000737:chemistry*; D000588:Amines / Q000737:chemistry*; D000605:Amino Alcohols / Q000138:chemical synthesis*; D001372:Aza Compounds / Q000737:chemistry; D001643:Bridged Bicyclo Compounds / Q000138:chemical synthesis; D002384:Catalysis; D003500:Cyclization; D006860:Hydrogen Bonding; D007659:Ketones / Q000138:chemical synthesis*; D008956:Models, Chemical; D009284:Naphthols / Q000737:chemistry; D009603:Nitroso Compounds / Q000138:chemical synthesis; D012997:Solvents / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: C518382:1-amino-3,4-diol; D000143:Acids; D000466:Alkadienes; D000588:Amines; D000605:Amino Alcohols; D001372:Aza Compounds; D001643:Bridged Bicyclo Compounds; D007659:Ketones; D009284:Naphthols; D009603:Nitroso Compounds; D012997:Solvents