Pd-Catalyzed Direct C–H Alkenylation and Allylation of Azine <i>N</i>-Oxides
作者:Fares Roudesly、Luis F. Veiros、Julie Oble、Giovanni Poli
DOI:10.1021/acs.orglett.8b00689
日期:2018.4.20
A Pd-catalyzed direct C2-alkenylation of azine N-oxides with allyl acetate is disclosed. The products are formed through an allylation/isomerization cascade process. The use of a tri-tert-butylphosphonium salt as the ligand precursor and KF is mandatory for optimal yields. When cinnamyl acetate is used, the same catalytic system promotes C2-cinnamylation of the azine N-oxide without subsequent isomerization
Iodo- or 2-bromopyridine N-oxides were readily magnesiated with i-PrMgCl·LiCl via the iodine or bromine−magnesium exchange. The bromine adjacent to pyridineN-oxide (at the 2- or 6-position) can be regioselectively magnesiated in the presence of other position substituted halogens. This method was tested in various substituted pyridineN-oxide systems, and has been successfully applied to the total