"Low-coordinate" 1,2-oxaphosphetanes - a new opportunity in coordination and main group chemistry.

While 1,2σ5λ5-oxaphosphetanes are well known intermediates from the Wittig-reaction, no 1,2σ3λ3-oxaphosphetanes have been described, so far. Herein, we present the first synthesis of 1,2σ3λ3-oxaphosphetanes derived from their κP-Mo(CO)5 complexes and first investigations towards metal coordination and P-oxidation. Bonding, ring strain energy and potential retro-[2+2] cycloaddition reactions of the 1,2-oxaphosphetane ring were studied by DFT methods.

Ring opening of a sterically crowded 1,2-oxaphosphetane complex.

The first example of a ring opening reaction of a 1,2-oxaphosphetane complex is reported, i.e., water in the presence of [Li(12-crown-4)]Cl furnished a C-OH functional phosphinito complex. Employment of the latter in ring forming reactions with Me2ECL2 (E = Si, Ge) using different nitrogen bases is also described.

Synthesis of a monomolecular anionic FLP complex.

Despite intense research in FLP chemistry, nothing is known about monomolecular anionic FLPs and/or complexes thereof. Herein, synthesis and reaction of the first anionic FLP complex is described using [(OC)5W{(Me3Si)2HCP(H)OLi(12-crown-4)}], Cy2BCl and subsequent deprotonation by KHMDS. The obtained anionic FLP complex reacts readily with CO2 in a concerted manner.

A novel route to C-unsubstituted 1,2-oxaphosphetane and 1,2-oxaphospholane complexes.

The synthesis of 1,2-oxaphosphetane complexes and 1,2-oxaphospholane complex bearing only substituents at phosphorus is reported using the reaction of Li/Cl phosphinidenoid complex with 2-iodoethanol or 3-bromo-propane-1-ol and the subsequent dehydrohalogenation using KHMDS. In contrast, the reaction of complex with (t)BuLi leads selectively to the formation of phosphinito complex .