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The first donor–acceptor complex of a silaaldehyde, with the general formula (NHC)(Ar)Si(H)OGaCl3 (NHC=N‐heterocyclic carbene), was synthesized using the reaction of silyliumylidene–NHC complex [(NHC)2(Ar)Si]Cl with water in the presence of GaCl3. Conversion of this complex to the corresponding silacarboxylate dimer [(NHC)(Ar)SiO2GaCl2]2, free silaacetal ArSi(H)(OR)2, silaacyl chloride (NHC)(Ar)Si(Cl)OGaCl3, and phosphasilene–NHC adduct (NHC)(Ar)Si(H)PTMS unveil its true potential as a synthon in silacarbonyl chemistry. The first silicon analogue of an aldehyde stabilized with an external Lewis base and Lewis acid was successfully isolated and characterized. It shows unique reactivity mimicking the behavior of carbonyl congeners and provides access to various classes of silacarbonyl derivatives. [ABSTRACT FROM AUTHOR]

An approach to novel P-functional chloroformylphosphane complexes is described using the synthetic potential of lithium/halogeno phosphinidenoid tungsten(0) complexes. Similarly to transition-metal-free chloroformylphosphanes, the obtained complexes tend to eliminate CO via P-C bond cleavage to give the corresponding P-chlorophosphane complex derivatives. Nevertheless, this method allowed the isolation of the first complex derivatives, which will open new synthetic perspectives in organophosphorus chemistry. [ABSTRACT FROM AUTHOR]

Oxidation of Li/X phosphinidenoid complex 2, obtained via selective deprotonation from the P-H precursor 1, with [Ph3C]BF4 led to the formation of two P-F substituted diorganophosphane complexes 6, 7; the latter tautomer 7 formed via H-shift from 6. In contrast, oxidation of 2 with [( p-Tol)3C]BF4 led to three major and one minor intermediates at low temperature, which we tentatively assign to two pairs of P-C atropisomers 10 a, a′ and 10 c, c′ and which differ by the relative orientations of their CH(SiMe3)2 and W(CO)5 groups. Conversion of all isomers led finally to complex 11 having a ligand with a long PC bond to the central trityl* carbon atom, firmly established by single-crystal X-ray analysis. DFT calculations at the B3LYP/def2-TZVPP//BP86/def2-TZVP level of theory on real molecular entities revealed the structures of the in situ formed combined singlet diradicals ( 4+ 5 and 5+ 9) and the nature of intermediates on the way to the final product, complex 11. Remarkable is that all isomers of 11 possess relative energies in the narrow energy regime of about 20 kcal mol−1. A preliminary study revealed that complex 11 undergoes selective PC bond cleavage at 75 °C in toluene solution. [ABSTRACT FROM AUTHOR]

Stereochemically pure di(1R,2S,5R)-menthyl (S)- and (R)-2-hydroxy-3-chloropropylphosphonates were synthesized by reaction of di(1R,2S,5R)-menthyl ketophosphonate with chiral complexes prepared from sodium borohydride and (R,R)-(+)-tartaric acid or with (S,S)-(-)-tartaric acid. Dimenthyl 2-hydroxy-3-chloropropylphosphonate was utilized as a chiron for the preparation of biologically active products. [ABSTRACT FROM AUTHOR]

Oxidation of in situ generated Li/X phosphinidenoid complexes[(OC)5W{(Me3Si)2CHP(X)Li/12-crown-4}](X =F (2), Cl (6)) with TEMPO at −78°C led to the lithium halogenophosphinite complexes [(OC)5W{(Me3Si)2CHP(X)OLi/12-crown-4}] (4) via an unknown pathway possibly involving transient P-nitroxyl complex derivatives (3). Whereas 4a(X = F) could be isolated directly, 4b(X= Cl) underwent facile hydrolysis to give the lithium phosphonitecomplex [(OC)5W{(Me3Si)2CHP(OH)OLi/12-crown-4}](7) as the final product; the structures of complexes 4aand 7were firmly established by single-crystalX-ray analysis. DFT calculations on the assumed intermediate P-nitroxyl complexes 3a,breveala preference for homolytic N–O over P–O bond cleavage,as underlined by the small bond dissociation energies (in kcal/mol: 3a, P–O 53.2 and N–O 26.0; 3b,P–O 35.4 and N–O 20.8). [ABSTRACT FROM AUTHOR]