Dramatic Effect of γ-Heteroatom Dienolate Substituents on Counterion Assisted Asymmetric Anionic Amino-Cope Reaction Cascades
作者:Pradipta Das、Michael D. Delost、Munaum H. Qureshi、Jianhua Bao、Jason S. Fell、Kendall N. Houk、Jon T. Njardarson
DOI:10.1021/jacs.1c00745
日期:2021.4.21
appear to proceed via the same pathway as the fluoride albeit with the added twist of a 3-exo-trig cyclization to yield chiral cyclopropane products with three stereocenters. When this same class of nucleophiles is substituted with a γ-nitro group, the Mannich-initiated cascade is now diverted to a β-lactam product instead of the amino-Cope pathway. These anionic asymmetric cascades are solvent- and counterion-dependent
Alkadiene derivatives, their preparation, and pharmaceutical
申请人:Rhone-Poulenc Sante
公开号:US04886835A1
公开(公告)日:1989-12-12
Substituted alkadienes of the formula: ##STR1## in which R.sub.1 is hydroxy or acetoxy, R.sub.2 is hydrogen, carboxy, alkoxycarbonyl, phenyl or benzoyl, and R.sub.3 is alkylthio or alkoxy and R.sub.4 is naphthoyl or optionally substituted benzoyl, or R.sub.3 is alkoxycarbonyl, cycloalkyloxycarbonyl or cyano and R.sub.4 is alkyl, naphthyl, optionally substituted phenyl, alkylthio, naphthylmethanethio, optionally substituted benzylthio, optionally substituted phenylthio, naphthylthio, phenethylthio or allylthio, or R.sub.3 and R.sub.4 form, with the carbon atom to which they are attached, a ring-system of formula: ##STR2## in which R.sub.5 is hydrogen or alkoxy and X is methylene or S inhibit 5-lipoxygenase and are useful, for example, as anti-inflammatories.
AbstractReaction of ammoniumylides with alkyl thiocyanates in aqueous and non-aqueous media is described. The reaction leads to alkyl thio-substituted acetophenones via addition of ammoniumylides to alkyl thiocyanates in organic solvents or in situ generated thiolate anions in aqueous media. Graphical abstract
Rh/DuanPhos-Catalyzed Asymmetric Hydrogenation of β-Acetylamino Vinylsulfides: An Approach to Chiral β-Acetylamino Sulfides
作者:Wenchao Gao、Hui Lv、Xumu Zhang
DOI:10.1021/acs.orglett.7b01115
日期:2017.6.2
Rh/DuanPhos-catalyzed asymmetric hydrogenation of challenging beta-acetylamino vinylsulfides has been developed; affording chiral beta-acetylamino, sulfides with high yield's and excellent ee's (up to, 99% ee). This novel methodology provides an efficient and' concise, synthetic route, to chiral beta-acetylamino sulfides. The potential utility of this protocol in the synthesis of Apremilast has also been disclosed.