TY - JOUR
T1 - An Intramolecular Wittig Approach toward Heteroarenes
T2 - Synthesis of Pyrazoles, Isoxazoles, and Chromenone-oximes
AU - Khairnar, Pankaj V.
AU - Lung, Tsai Hui
AU - Lin, Yi Jung
AU - Wu, Chi Yi
AU - Koppolu, Srinivasa Rao
AU - Edukondalu, Athukuri
AU - Karanam, Praneeth
AU - Lin, Wenwei
PY - 2019/6/7
Y1 - 2019/6/7
N2 - α-Halohydrazones/ketoximes are transformed into trisubstituted pyrazoles/disubstituted isoxazoles by treatment with phosphine, acyl chloride, and a base. Mechanistic investigations revealed the in situ formation of azo/nitroso olefin intermediates which underwent a tandem phospha-Michael/N- or O-acylation/intramolecular Wittig reaction to afford the heteroarenes in moderate to good yields. Further, proper functionalization of α-haloketoximes and a change of conditions allowed the chemoselective synthesis of chromenone-oximes as well as rearranged isoxazoles, thereby realizing a diversity-oriented synthesis.
AB - α-Halohydrazones/ketoximes are transformed into trisubstituted pyrazoles/disubstituted isoxazoles by treatment with phosphine, acyl chloride, and a base. Mechanistic investigations revealed the in situ formation of azo/nitroso olefin intermediates which underwent a tandem phospha-Michael/N- or O-acylation/intramolecular Wittig reaction to afford the heteroarenes in moderate to good yields. Further, proper functionalization of α-haloketoximes and a change of conditions allowed the chemoselective synthesis of chromenone-oximes as well as rearranged isoxazoles, thereby realizing a diversity-oriented synthesis.
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U2 - 10.1021/acs.orglett.9b01395
DO - 10.1021/acs.orglett.9b01395
M3 - Article
C2 - 31117709
AN - SCOPUS:85067025370
VL - 21
SP - 4219
EP - 4223
JO - Organic Letters
JF - Organic Letters
SN - 1523-7060
IS - 11
ER -