Facile Synthesis of Azaspirocycles via Iron Trichloride-Promoted Cyclization/Chlorination of Cyclic 8-Aryl-5-aza-5-tosyl-2-en-7-yn-1-ols
摘要:
A simple and efficient FeCl3-promoted cyclization/chlorination of cyclic tosylamine-tethered 8-aryl-2-en-7-yn-1-ols was observed. The reaction proceeded instantaneously at 23 degrees C in air to afford (Z)-4-(arylchloromethylene)-substituted azaspirocycles in good to excellent yields. This transformation can also be applied to the synthesis of spirocarbocyclic analogues from cyclic 8-aryl-2-en-7-yn-1-ols and FeCl3.
Diastereoselective Synthesis of 2-Arylmethylene-6-hydroxyspiro[4.5]deca-7-ones via FeCl3·6H2O-Catalyzed Spiroannulation/Hydride Transfer of 6-(5-Arylpent-4-yn-1-yl)-7-oxabicyclo[4.1.0]heptan-2-ols
摘要:
In the presence of a catalytic amount of FeCl3 center dot 6H(2)O, 6-(5-arylpent-4-yn-1-yl)-7-oxabicyclo[4.1.0]heptan-2-ols underwent attack of the pendant acetylene at the iron-activated oxirane to give a vinylic carbocation. Hydride transfer from the carbinol carbon to the newly formed cation center furnished 2-arylmethylene-6-hydroxyspiro[4.5]deca-7-ones in excellent stereoselectivity and good yields.