Synthesis of β-azidoketones, β-azidoacids and related compounds
A chiral (salen)Al complex catalyzes the highly enantioselective conjugate addition of carbon- and nitrogen-based nucleophiles to various acyclic α,β-unsaturated ketones providing access to a wide range of useful chiral building blocks in high yield and enantiomeric excess.
M. S. Taylor, D. N. Zalatan, A. M. Lerchner, E. N. Jacobsen, J. Am. Chem. Soc., 2005, 127, 1313-1317.
Tertiary amines catalyze a β-azidation of α,β-unsaturated carbonyl compounds with a 1:1 mixture of TMSN3 and AcOH as azide source. Tertiary amines, either in solution or bound to a solid support, can be used.
D. J. Guerin, T. E. Horstmann, S. J. Miller, Org. Lett., 1999, 1, 1107-1109.
Amberlite IRA900N3 is an excellent and recyclable organocatalyst for the azidation of α,β-unsaturated ketones with trimethylsilyl azide under solvent-free conditions. This procedure is a green tool for the preparation of β-azido ketones under mild conditions with good yields.
L. Castrica, F. Fringuelli, L. Gregoli, F. Pizzo, L. Vaccaro, J. Org. Chem., 2006, 71, 9536-9539.
An iron-catalyzed acyl-azidation of alkenes provides unsymmetrical β-azido ketones under mild reaction conditions from aromatic aldehydes or aliphatic aldehydes as the acyl radical precursors, TMSN3 as the azido source, and TBHP as the initiator. The synthesized unsymmetrical β-azido ketones can be easily transformed into valuable functionalized compounds.
L. Ge, Y. Li, H. Bao, Org. Lett., 2019, 21, 256-260.
A mild oxidation of selected anions (N3-, SCN-, I-, and Br-) by ceric ammonium nitrate (CAN) in the presence of substituted cyclopropyl alcohols provides β-functionalized ketones in short reaction times. This method provides an alternative pathway to important starting materials and intermediates in organic synthesis.
J. Jiao, L. X. Nguyen, D. R. Patterson, R. A. Flowers II, Org. Lett., 2007, 9, 1323-1326.
Chiral N,N'-dioxide/Fe(OTf)2 complexes catalyze an unprecedented highly diastereo- and enantioselective bromoazidation of α,β-unsaturated ketones. An array of aryl, heteroaryl, and alkyl substituted α,β-unsaturated ketones were transformed to the corresponding α-bromo-β-azido ketones in high yields with excellent diastereo- and enantioselectivities. The catalytic system was also applicable for chloroazidations and iodoazidations.
P. Zhou, L. Lin, L. Chen, X. Zhong, X. Liu, X. Feng, J. Am. Chem. Soc., 2017, 139, 13414-13419.
A chiral iron(II) complex catalyzes a regio- and enantioselective α-halo-β-azido difunctionalization of both α,β-unsaturated amides and α,β-unsaturated esters under mild reaction conditions to provide a broad spectrum of valuable functionalized amides and esters.
P. Zhou, X. Liu, W. Wu, C. Xu, X. Feng, Org. Lett., 2019, 21, 1170-1175.