Cobalt-Catalyzed Cross-Coupling Reactions of Alkyl Halides with Allylic and Benzylic Grignard Reagents and Their Application to Tandem Radical Cyclization/Cross-Coupling Reactions
Details of cobalt-catalyzed cross-coupling reactions of alkyl halides with allylic Grignard reagents are disclosed. A combination of cobalt(II) chloride and 1,2-bis(diphenylphosphino)ethane (DPPE) or 1,3-bis(diphenylphosphino)propane (DPPP) is suitable as a precatalyst and allows secondary and tertiary alkyl halides--as well as primary ones--to be employed as coupling partners for allyl Grignard reagents
A new synthetic method for functionalized cyclopentanones was developed on the basis of a [3+2] cycloaddition reaction of a 1-(methylthio)-2-siloxyallyl cationic species and olefins. Allyl acetates 1a and 1b, which are the precursors of the allyl cationic species, are easily prepared in three or four steps from commercially available compounds. Under the influence of EtAlCl2 or AlCl3, 1a or 1b reacted
1‐dimethylallyl)hydrazones was developed utilising Thomson's traceless bond construction. This type of [3,3]‐sigmatropicrearrangement is catalysed by the Bronsted acid triflimide and liberates only gaseous by‐products. The required N‐Boc‐N‐allylhydrazine precursor is available in three steps starting from a known diazene using biocatalytic aldol addition and Tebbe olefination as key steps. Allylhydrazones are prepared