Oxa-Michael Addition to alpha,beta-Unsaturated Nitriles: An Expedient Route to gamma-Amino Alcohols and DerivativesGuo, B., Zijlstra, D. S., de Vries, J. G. & Otten, E., 9-Jul-2018, In : ChemCatChem. 10, 13, p. 2868-2872 5 p.
Research output: Contribution to journal › Article › Academic › peer-review
Water addition to alpha,beta-unsaturated nitriles would give facile access to the -hydroxy-nitriles, which in turn can be hydrogenated to the gamma-amino alcohols. We have previously shown that alcohols readily add in 1,4-fashion to these substrates using Milstein's Ru(PNN) pincer complex as catalyst. However, attempted water addition to alpha,beta-unsaturated nitriles gave the 3-hydroxynitriles in mediocre yields. On the other hand, addition of benzyl alcohol proceeded in excellent yields for a variety of -substituted unsaturated nitriles. Subsequent treatment of the benzyl alcohol addition products with TMSCl/FeCl3 resulted in the formation of 3-hydroxy-alkylnitriles. The 3-benzyloxy-alkylnitriles obtained from oxa-Michael addition also could be hydrogenated directly in the presence of acid to give the amino alcohols as their HCl salts in excellent yields. Hydrogenation under neutral conditions gave a mixture of the secondary and tertiary amines. Hydrogenation in the presence of base and Boc-anhydride gave the orthogonally bis-protected amino alcohols, in which the benzyl ether can subsequently be cleaved to yield Boc-protected amino alcohols. Thus, a variety of molecular scaffolds with a 1,3-relationship between O- and N-functional group is accessible starting from oxa-Michael addition of benzyl alcohol to alpha,beta-unsaturated nitriles.
|Number of pages||5|
|Publication status||Published - 9-Jul-2018|
- oxa-Michael addition, amino alcohols, hydrogenation, nitriles, pincer ligand, ruthenium, ENANTIOSELECTIVE BETA-BORYLATION, REDOX-FLOW BATTERY, TRIETHANOLAMINE STEARATE, UNSATURATED NITRILES, CARBOXYLIC-ACIDS, LIGAND, WATER, ACCEPTORS, COMPLEX, HYDROGENATION