Categories: C-O Bond Formation
Synthesis of Hemiaminals and Hemiaminal ethers
An enantioselective addition of alcohols to imines proceeds in the presence of a catalytic amount of a chiral phosphoric acid catalyst to give the respective chiral N,O-aminals in excellent yield and enantioselectivity.
G. Li, F. R. Fronczek, J. C. Antilla, J. Am. Chem. Soc., 2008, 130, 12216-12217.
Unusual N-Acyl-N,O-acetals are present in a number of bioactive natural products and can act as a synthetic precursor to unstable reactive N-acylimines. Various N-acyl-N,O-acetals can be prepared under mild conditions mediated by titanium ethoxide (Ti(OEt)4). The method also offers a new strategy to make other O-alkyl-N,O-acetals.
M. Li, B. Luo, Q. Liu, Y. Hu, A. Ganesan, P. Huang, S. Wen, Org. Lett., 2014, 16, 10-13.
A highly efficient ruthenium-catalyzed stereospecific N-demethylative rearrangement of isoxazolidines gives synthetically useful N-H-1,3-oxazinanes. 1,3-Oxazinanes are useful building blocks, which can be converted to N-H-1,3-aminoalcohols in a subsequent step.
C.-Z. Yao, Z.-F. Xiao, X.-S. Ning, J. Liu, X.-W. Zhang, Y.-B. Kang, Org. Lett., 2014, 16, 5824-5826.
ert-Butylperoxyamido acetals can be generated in high yields under mild conditions via oxidative functionalization of C-H bonds adjacent to the amide nitrogen atom. Treatment with Grignard reagents enables the synthesis of α-substituted amides.
H. Yu, J. Shen, Org. Lett., 2014, 16, 3204-3207.