Formal [4+3], [4+2], [4+1] and [2+1] cycloadditions and acid-base reaction of 2-methyl-1,3-dimorpholino-1,3-butadiene with Fischer carbene complexes

Article abstract of DOI:10.1002/chem.19970031012

2-Methyl-1,3-dimorpholino-1,3-butadiene 1 reacted with α,β-unsaturated Fischer carbene complexes to give a wide range of different products depending on the substitution pattern. Thus, seven-membered rings (4, 5 and 6) could be obtained from chromium comp