Kishner-Leonard elimination

Elimination of adjacent substituents (Kishner-Leonard eliminations)... 

The Myers two-step, single-flask procedure differs from the Cram procedure in that the requisite hydrazones are more reliably made and do not require isolation. The reduction of simple aliphatic hydrazones generally takes place at ambient temperature, whereas sterically hindered hydrazones required some heating (100 °C) for the reaction to proceed at a reasonable rate. Complex structures such as the steroid hecogenin (12, eq 5), and other tertiary hydrazones, are efficiently reduced in high yield. The morphine derivative naloxone (14, eq 6) underwent the expected Kishner-Leonard elimination under the standard conditions. ... 

Leonard, N. J., Gelfand, S. The Kishner reduction-elimination. II. a-Substituted pinacolones. J. Am. Chem. Soc. 1955, 77, Z272-Z278. 

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