Transition-Metal-Like Reversible Cycloadditions of [tBuSP-W(CO)_5] with Alkenes and Alkynes

摘要

tert-Butylthiophosphinidene complex [tBuSPW( CO)_5] was generated by dissociation of 1-(tert-butylthio) phosphirane-W(CO)_5 complex under mild conditions. The formation of transient [tBuSP-W(CO)_5] was indicated by trapping reactions with 2,3-dimethyl-1,3-butadiene, alkynes, phenanthrene-9,10-dione, and methanol. The LUMO of [MeSP-W(CO)_5] is significantly lower in energy than those of [Me_2NP-W(CO)_5], [MeOP-W(CO)_5], and [Me_2PP-W(CO)_5]. The HOMO of [MeSP-W(CO)_5] contains a significant contribution from the in-plane lone pair of P and the LUMO shows a typical p~* characteristic. Since stabilized by sulfur lone pair and coordinated by W(CO)_5, [tBuSP-W(CO)_5] undergoes facile and reversible cycloadditions with alkenes and alkynes.