Highly hindered γ-PIII-functionalised alkoxo–lithium complexes: syntheses and structures of [Li(µ-OCBut2CH2PR2)]2(R = Me or Ph) and [Li(µ-OCBut2CH2PPh2)2Li(OCBut2)]

Abstract

Reaction of Li(CH₂PR₂)(tmeda)(R = Me or Ph; tmeda =N,N,N′,N′-tetramethylethylenediamine) with di-t-butyl ketone yields [[graphic omitted]R₂)]₂[R = Me, (1)] or [[graphic omitted]i(OCBu^t₂)], (3); compound (2), the diphenyl analogue of (1), is accessible either by reaction of (3) and further Li(CH₂PPh₂)(tmeda) or by lithiation of Ph₂PCH₂C(OH)Bu^t₂: the γ-P-functionalised lithium alkoxides (1)–(3) are shown by X-ray crystallography to have Li–P bonds and very short Li–O and Li ⋯ Li contacts, and compound (3) is structurally similar to the adduct proposed as an intermediate in the important carbanionic alkylation of a ketone.