Microwave-assisted [2 + 3] cycloaddition of nitrones to platinum-(ii) and -(iv) bound organonitriles
Abstract
The coordinated EtCN in the anionic platinum(II)
[Ph3PCH2Ph][PtCl3(EtCN)], the neutral platinum(II)
[PtCl2(EtCN)2] or the neutral platinum(IV)
[PtCl4(EtCN)2] complexes undergo [2 + 3] cycloadditions with cyclic non-aromatic nitrones and these reactions are greatly accelerated by microwave irradiation, to give, with a high stereoselectivity, complexes with bicyclic fused oxadiazolines as a racemic mixture in 60–90% yields, while acyclic nitrones are much less reactive and give a mixture of two diastereoisomers in the ratio 1 ∶ 1. The new bicyclic