Science of Synthesis

Spitzner, D., Science of Synthesis, (2005) 15, 33.

The heteroaromatic portion ‌83‌ of the natural product rubrolone can be prepared by a three-component, one-pot pyridine synthesis (‌Scheme 29‌). Lithiated acetone dimethylhydrazone[‌142‌,‌143‌] is transformed into its cuprate (with CuSPh[‌144‌] or the homocuprate from CuI and Me2S[‌145‌]); this cuprate undergoes a conjugate addition to an α,β-unsaturated ketone, in this case, cyclopent-2-enone. The resulting enolate is trapped with the α-oxo cyanide, followed by elimination of cyanide, to give the monohydrazone ‌82‌ of a 1,5-dicarbonyl compound. This intermediate cyclizes and aromatizes (elimination of Me2NH) upon treatment with glacial acetic acid to give the pyridine.[‌146‌]

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References

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• 8.Meeeee-Meee, (8888) M 8e, 888.