Synthesis of 2-azaspiro[4.6]undec-7-enes from N -tosyl- N -(3-arylpropargyl)-tethered 3-methylcyclohex-2-en-1-ols

Article abstract of DOI:10.1021/jo301764g

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.