Catalytic aza-Wittig cyclizations for heteroaromatic synthesis.
The first examples of heterocycle synthesis by iminophosphorane formation/intramolecular aza-Wittig cyclizations that are catalytic in the organophosphorus component are reported. The reaction has been demonstrated in the synthesis of both azine (phenanthridine) and azole (benzoxazole) heterocycles. Catalyst loadings down to 1 mol % have been used with little or no loss in reaction efficiency. The intimate involvement of the phosphine oxide in the catalytic cycle has been verified by in situ infrared spectroscopy.
Marsden
Stephen P
SP
School of Chemistry, University of Leeds, Leeds, UK. s.p.marsden@leeds.ac.uk
McGonagle
Alison E
AE
McKeever-Abbas
Ben
B
D001372:Aza Compounds / Q000737:chemistry*; D001583:Benzoxazoles / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D003500:Cyclization; D015394:Molecular Structure; D013055:Spectrophotometry, Infrared
D001372:Aza Compounds; D001583:Benzoxazoles