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.
Synthesis of 2-Azaspiro[4.6]undec-7-enes from N-Tosyl-N-(3-arylpropargyl)-Tethered 3-Methylcyclohex-2-en-1-ols
摘要:
The FeCl3-promoted synthesis of 2-azaspiro[4.6]-undec-7-ene rings proceeds via ring expansion/cyclization/chlorination of N-tosyl-N-(3-arylpropargyl)-tethered 6-methylbicyclo[4.1.0]heptan-2-ols. This azaspirocyclic ring skeleton can also be obtained in one pot from the tert-butyldimethylsilyl-protected N-tosyl-N-(3-arylpropargyl)-tethered 3-methylcyclohex-2-en-1-ols and diethylzinc/diiodomethane.