92298-90-3Relevant academic research and scientific papers
Traceless Isoprenylation of Aldehydes via N-Boc-N-(1,1-dimethylallyl)hydrazones
Heerdegen, Desirée,Junker, Julia,Dittrich, Sebastian,Mayer, Peter,Bracher, Franz
, p. 3680 - 3687 (2020/06/02)
A short isoprenylation protocol starting from non-conjugated N-Boc-N-(1,1-dimethylallyl)hydrazones was developed utilising Thomson's traceless bond construction. This type of [3,3]-sigmatropic rearrangement is catalysed by the Br?nsted 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 via condensation with appropriate aldehydes. Scope and limitations of the [3,3]-sigmatropic rearrangements are analysed.
Cobalt-catalyzed cross-coupling reactions of alkyl halides with allylic and benzylic grignard reagents and their application to tandem radical cyclization/cross-coupling reactions
Ohmiya, Hirohisa,Tsuji, Takashi,Yorimitsu, Hideki,Oshima, Koichiro
, p. 5640 - 5648 (2007/10/03)
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. The reaction offers a facile synthesis of quaternary carbon centers. which has practically never been possible with palladium, nickel, and copper catalysts. Benzyl, methallyl, and crotyl Grignard reagents can all couple with alkyl halides. The benzylation definitely requires DPPE or DPPP as a ligand. The reaction mechanism should include the generation of an alkyl radical from the parent alkyl halide. The mechanism can be interpreted in terms of a tandem radical cyclization/cross-coupling reaction. In addition, serendipitous tandem radical cyclization/cyclopropanation/carbonyl allylation of 5-alkoxy-6-halo-4-oxa-1-hexene derivatives is also described. The intermediacy of a carbon-centered radical results in the loss of the original stereochemistry of the parent alkyl halides, creating the potential for asymmetric cross-coupling of racemic alkyl halides.
Cobalt-catalyzed coupling reaction of alkyl halides with allylic grignard reagents
Tsuji, Takashi,Yorimitsu, Hideki,Oshima, Koichiro
, p. 4137 - 4139 (2007/10/03)
Facile construction of quaternary carbon centers: The cobalt-catalyzed coupling reaction of not only primary and secondary but also tertiary alkyl halides with allylic Grignard reagents proceeds smoothly (see scheme; dppp = 1,3-bis(diphenylphosphanyl)prop
