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
A New, Simple, and General Synthesis of N-Oxides of Iodopyridines and Iodoquinolines via the Diazotization–Iodination of Heterocyclic Amino N-Oxides in the Presence of p-Toluenesulfonic Acid in Water
Abstract The diazotization of a series of N-oxides of aminopyridines and aminoquinolines under the action of sodium nitrite in the presence of KI and p-TsOH in water at room temperature leads to the formation of the corresponding N-oxides of iodopyridines and iodoquinolines in high yields. The method has a general character and can be used for the preparation of 3-, 2-, and 4- N-oxides of iodopyridines
Hydroheteroarylation of Unactivated Alkenes Using <i>N</i>-Methoxyheteroarenium Salts
作者:Xiaoshen Ma、Hester Dang、John A. Rose、Paul Rablen、Seth B. Herzon
DOI:10.1021/jacs.7b02388
日期:2017.4.26
reductive coupling of unactivated alkenes with N-methoxy pyridazinium, imidazolium, quinolinium, and isoquinolinium salts under hydrogen atom transfer (HAT) conditions, and an expanded scope for the coupling of alkenes with N-methoxy pyridinium salts. N-Methoxy pyridazinium, imidazolium, quinolinium, and isoquinolinium salts are accessible in 1-2 steps from the commercial arenes or arene N-oxides (25-99%)
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