Ring-opening cross metathesis of 1,3-cyclopentadiene-heterodienophile cycloadducts to produce cyclic hydrazines and hydroxylamines

The combination of a hetero-Diels–Alder reaction of a N–N or N–O heterodienophile and 1,3-cyclopentadiene with ruthenium catalyzed ring-opening cross metathesis (ROCM) produces new functionalized heterocyclic five-membered rings. The cycloadduct of 1,3-cyclopentadiene and diethyl azidodicarboxylate underwent ROCM to give a 2.5:1 (E:Z) mixture of diastereomeric cyclic hydrazines. This substrate also appears to be a suitable precursor for ring-opening polymerization. The cycloadduct of 1,3-cyclopentadiene and an acyl nitroso compound underwent ROCM to give a mixture of four cyclic hydroxylamines. These results represent the first examples of ROCM on strained cyclic substrates containing multiple heteroatoms.