Synthesis and coordination chemistry of enantiopure t-BuMeP(O)H

Abstract

Both enantiomers of the optically pure Secondary Phosphine Oxide (SPO) t-BuMeP(O)H (1) have been obtained by deboronation of phosphinous acid-borane t-BuMeP(O)H·BH₃ (3) with HBF₄ followed by hydrolysis of the intermediate adduct t-BuMeP(O)H·BF₃ (1·BF₃), which has been isolated and crystallographically characterised. Complexes [MCl(COD)(κP-(R)-1)] (M = Ir, Rh; 4 and 7 respectively) have been detected in solution but could not be isolated while trans-[RhCl(CO)(κP-(S)-1)₂] (9) has been successfully obtained in good yield. Gold complex [AuCl(κP-(S)-1)] (10) has been prepared and its crystal structure shows the presence of aurophilic interactions. Three new ruthenium complexes ([RuCl₂(η⁶-p-cymene)(κP-(R)-1)], 12), ([RuCl₂(CO)₃(κO-(S)-1)], 13) and trans-([RuCl₂(CO)₂(κP-(S)-1)₂], 14) have been synthesised and fully characterised, including the crystal structure of 12. Four palladium coordination compounds have been prepared: trans-[PdCl₂(κP-(S)-1)₂] (trans-15), [Pd(μ-Cl)(κP-(S)-1)₂]₂ (16·OH and 16·BF₂) and [Pd(μ-OAc)(κP-(S)-1)₂] (17) and the crystal structure of complex 16·OH proves the pseudobidentate coordination of the two molecules of 1. Three organometallic allylpalladium complexes have been prepared namely [Pd(η³-Ph₂C₂H₃)Cl(κP-(S)-1)] (18) and [Pd(η³-Ph₂C₂H₃)(κP-(S)-1)₂] (19·OH and 19·BF₂). The crystal structure of 19·BF₂ constitutes the first allylpalladium-SPO complex reported to date.