Extending the Scope of the B(C6F5)3-Catalyzed C=N Bond Reduction: Hydrogenation of Oxime Ethers and Hydrazones
The B(C6F5)3-catalyzed hydrogenation is applied to aldoxime triisopropylsilyl ethers and hydrazones bearing an easily removable phthaloyl protective group. The C=N reduction of aldehyde-derived substrates (oxime ethers and hydrazones) is enabled by using 1,4-dioxane as the solvent known to participate as the Lewis-basic component in FLP-type heterolytic dihydrogen splitting. More basic ketone-derived hydrazones act as Lewis bases themselves in the FLP-type dihydrogen activation and are therefore successfully hydrogenated in nondonating toluene. The difference in reactivity between aldehyde- and ketone-derived substrates is also reflected in the required catalyst loading and dihydrogen pressure.
Mohr, Jens,Porwal, Digvijay,Chatterjee, Indranil,Oestreich, Martin
supporting information
p. 17583 - 17586
(2015/12/05)
A convenient synthesis of 1-alkyl-1-phenylhydrazines from N-aminophthalimide
N-Alkylaminophthalimides were synthesized by condensation of N-aminophthalimide with aldehydes, and subsequent reduction of the intermediate with pyridine-borane in acetic acid. N-Phenylation and removal of the phthalimide group gave 1-alkyl-1-phenylhydrazines in high yield.