Rh(III)-Catalyzed Regioselective Synthesis of Pyridines from Alkenes and α,β-Unsaturated Oxime Esters
作者:Jamie M. Neely、Tomislav Rovis
DOI:10.1021/ja3104389
日期:2013.1.9
O-pivaloyl oximes are coupled to alkenes by Rh(III) catalysis to afford substituted pyridines. The reaction with activated alkenes is exceptionally regioselective and high-yielding. Mechanistic studies suggest that heterocycle formation proceeds via reversible C-H activation, alkene insertion, and a C-N bondformation/N-O bond cleavage process.
Dienediolates of unsaturated carboxylic acids in synthesis. Aldehydes and ketones from alkyl halides, by ozonolysis of β,γ-unsaturated α-alkyl carboxylic acids. The role of a tertiary amine in the cleavage of ozonides
A convenient two-step procedure for a two carbon homologativeconversion of alkyl halides into aldehydes and methyl ketones by α-alkylation of unsaturated carboxylic acids, followed by ozonolysis is developed and applied to the synthesis of ω-chloro aldehydes. Triethylamine is superior to dimethyl sulfide or triphenylphosphine for cleavage of the ozonides, except when aldol condensation side reactions
isolation and characterization of 19-oxo Δ20,21 secodine (2) is described. This compound is the first example of a stabilized, potentially reactive secodine intermediate in alkaloid synthesis. It cyclized to minovincine (1) in 77% yield in refluxing m-xylene.