The quest for new mild and selective modifications of natural structures: laccase-catalysed oxidation of ergot alkaloids leads to unexpected stereoselective C-4 hydroxylation.
Laccase-catalysed oxidation of ergot alkaloids in the absence of chemical mediators allowed the unexpected isolation of the mono-hydroxylated derivatives of compounds 2-7. Structure determination by NMR techniques clearly indicated that hydroxylation took place at the C-4 benzylic position. Quite notably, the proposed protocol allowed, for the first time, functionalisation at the C-4 position of the ergoline skeleton. Depending on the absence or on the presence of a C-10 α-methoxy substituent, hydroxylation was either stereoselective (furnishing C-4α OH derivatives) or gave rise to a C-4α/C-4β OH mixture in a 2:1 ratio, respectively.
Istituto di Chimica del Riconoscimento Molecolare, C.N.R. Via Mario Bianco, 9, 20131, Milano, Italy.
Cosimo
C
Chirivì
Gabriele
G
Fontana
Daniela
D
Monti
Gianluca
G
Ottolina
Sergio
S
Riva
Bruno
B
Danieli
D002384:Catalysis; D004876:Ergot Alkaloids / Q000737:chemistry*; D006900:Hydroxylation; D042845:Laccase / Q000737:chemistry* / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010084:Oxidation-Reduction; D013237:Stereoisomerism
D004876:Ergot Alkaloids; D042845:Laccase