Double intramolecular Diels–Alder reaction of α,β-unsaturated hydrazones: a new route to 2,2′-bipyridines
作者:Nicholas Bushby、Christopher J. Moody、Christopher J. Moody、David A. Riddick、Ian R. Waldron
DOI:10.1039/a901641d
日期:——
Heating the 1,3-diynyl bis-α,β-unsaturated hydrazones 3, 6 and 10 results in double intramolecular DielsâAlder reaction of the 1-azadienes, and after aromatisation by loss of dimethylamine, the formation of bipyridines 11â14.
Efficient One-Step Synthesis of Bis-Spiroketals from Diynediols by π-Lewis Acid-Catalyzed Hydroalkoxylation/Hydration
作者:Ivan Volchkov、Kamlesh Sharma、Eun Jin Cho、Daesung Lee
DOI:10.1002/asia.201100131
日期:2011.8.1
Spiroling out of control: An efficientone‐stepsynthesis of 5‐5‐5, 5‐5‐6, and 6‐5‐6 bis‐spiroketals from 4,6‐diyne‐1,n‐diols and 5,7‐diyne‐1,n‐diols has been developed with good yields. A mixture of cis‐ and trans‐bis‐spiroketals were generally obtained from each substrate and the isolated cis‐ and trans‐bis‐spiroketals undergo interconversion to reach their equilibrium composition (see scheme).