title: N-allyl-N-sulfonyl ynamides as synthetic precursors to amidines and vinylogous amidines. An unexpected N-to-C 1,3-sulfonyl shift in nitrile synthesis.
abstract: A detailed study of amidine synthesis from N-allyl-N-sulfonyl ynamides is described here. Mechanistically, this is a fascinating reaction consisting of diverging pathways that could lead to deallylation or allyl transfer depending upon the oxidation state of palladium catalysts, the nucleophilicity of amines, and the nature of the ligands. It essentially constitutes a Pd(0)-catalyzed aza-Claisen rearrangement of N-allyl ynamides, which can also be accomplished thermally. An observation of N-to-C 1,3-sulfonyl shift was made when examining these aza-Claisen rearrangements thermally. This represents a useful approach to nitrile synthesis. While attempts to render this 1,3-sulfonyl shift stereoselective failed, we uncovered another set of tandem sigmatropic rearrangements, leading to vinyl imidate formation. Collectively, this work showcases the rich array of chemistry one can discover using these ynamides.
authors.affiliation: Division of Pharmaceutical Sciences and Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53705, USA.
authors.forename: Kyle A
authors.initials: KA
authors.lastname: DeKorver
authors.forename: Whitney L
authors.initials: WL
authors.lastname: Johnson
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Richard P
authors.initials: RP
authors.lastname: Hsung
authors.forename: Huifang
authors.initials: H
authors.lastname: Dai
authors.forename: Jun
authors.initials: J
authors.lastname: Deng
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Lohse
authors.forename: Yan-Shi
authors.initials: YS
authors.lastname: Zhang
mesh_terms: D000498:Allyl Compounds / Q000737:chemistry*; D000578:Amidines / Q000138:chemical synthesis*; D000588:Amines / Q000737:chemistry*; D008024:Ligands; D015394:Molecular Structure; D009570:Nitriles / Q000138:chemical synthesis*; D013457:Sulfur Compounds / Q000737:chemistry*; D014753:Vinyl Compounds / Q000737:chemistry*
chemical_list: D000498:Allyl Compounds; D000578:Amidines; D000588:Amines; D008024:Ligands; D009570:Nitriles; D013457:Sulfur Compounds; D014753:Vinyl Compounds