The transition metal-catalyzed transfer of silicon nucleophiles [1] onto various electrophiles, has recently gained considerable attention, [2] owing to the development of readily available silicon pro-nucleophiles. In particular, the reagent developed by the Suginome group, which possesses a SiÀB linkage has become one of the major sources of nucleophilic silicon. [1a] This new method is particularly attractive, as it provides a facile access to metal-silicon reagents that render the use of any activating agents unnecessary.These metal-silicon intermediates allow the catalytic transfer of a silicon nucleophile onto various electrophiles; our interest lies in the addition of such species to aldehydes, thus generating a-hydroxysilanes. This type of C À Si bond formation as well as the hydroxy group is of crucial importance in organic synthesis. Moreover, a stereogenic center is formed in this process, thus generating possible opportunities for asymmetric catalysis.Optically active a-hydroxysilanes are a class of chiral organometallic compounds that contain a functional group. These molecules and their derivatives have been used for stereocontrolled C À C bond formation and rearrangements, which resulted in a wide variety of chiral organic compounds. [3][4][5][6][7] The majority of literature-known methods for the preparation of a-hydroxysilanes are based on the asymmetric reduction of acylsilanes [8] or the hydrogenation of enolsilanes. [9] However, the synthesis of acylsilanes usually requires several steps. [10] An alternative, but less used, approach is the one previously described, which includes the addition of a silicon nucleophile to a carbonyl compound. [11][12][13][14] Hiyama et al. introduced a fluoride-catalyzed SiÀ Si bond cleavage followed by the addition of released silicon nucleophiles to aldehydes. [11] However, yields were partially diminished by [1,2]-Brook rearrangement. Barrett and Hill [13] elaborated a practical procedure based on the addition of easy-to-form Me 2 PhSiLi to aliphatic and aromatic aldehydes, but the use of such strongly basic nucleophiles is not without problems for functionalized aldehydes.Recently, Oestreich described the racemic 1,2-addition of a silicon nucleophile to imines and aldehydes, and proposed a mechanism involving a CuÀSi intermediate as the silyl transfer species. [2d, 15] The mild copper-mediated generation of nucleophilic silicon from Si À B compounds might therefore be useful for catalytic one-step access to enantiomerically pure a-hydroxysilanes from readily available aldehydes.Herein, we report the first enantiomeric version of the 1,2addition of a silicon nucleophile to aromatic and aliphatic aldehydes catalyzed by copper(I) complexes.Our investigation started with benzaldehyde, which was selected as a model substrate for initial screening. The reaction of 1 a with Me 2 PhSiBpin (2; = Si À B, pin = pinacolato) [16] in the presence of CuF(PPh 3 ) 3 ·2 MeOH (3) [17] as the copper catalyst was completed in 2 h at room temperature, and resulted in the isola...

The transition metal-catalyzed transfer of silicon nucleophiles onto various electrophiles has recently gained considerable attention, due to the now readily available silicon pro-nucleophiles such as silylboronates. Our interest lies in the addition of such species to acid derivatives for the generation of acylsilanes. We report herein an efficient method to synthesize these compounds, starting from easyto-form anhydrides, with very good yields.

Posaconazole is a broad-spectrum triazole antifungal available as an oral suspension. Pharmacokinetic data showed a high variability of plasma posaconazole concentrations (PPCs) in patients, suggesting a potential interest in drug monitoring. The aim of our prospective study was to measure the PPCs in prophylactically treated patients to evaluate the impact of different factors on these concentrations. In 40 patients treated prophylactically with posaconazole for acute myeloid leukemia or myelodysplastic syndrome between February 2009 and August 2010, PPCs were measured at day 7 of treatment and then twice weekly. Demographic data, clinical data (including gastrointestinal disorders, comedications, and treatment compliance), caloric and fat intake, and biological data were collected and evaluated. We obtained 275 measurements of PPCs, with a median of 430 ng/ml. PPCs were significantly lower in patients with mucositis (P < 0.001), nausea (P ‫؍‬ 0.03), diarrhea (P ‫؍‬ 0.03), or vomiting (P ‫؍‬ 0.05). PPCs were higher in patients with a higher caloric intake (P ‫؍‬ 0.02), while the proportion of fat intake had no influence on PPCs (P ‫؍‬ 0.84). The concomitant use of proton pump inhibitors decreased the PPCs (P ‫؍‬ 0.02), while the use of tacrolimus increased the PPC (P ‫؍‬ 0.03). In the multivariate analysis, the factors influencing the PPCs independently were the concomitant use of tacrolimus (P < 0.001), the presence of mucositis (P ‫؍‬ 0.01), and food intake (P ‫؍‬ 0.02). Our study confirmed the high variability of posaconazole bioavailability and showed the significant influence of gastrointestinal disorders, food intake, and concomitant medication on the PPCs. However, the optimal PPCs still remain to be defined and correlated with clinical efficacy.

Dran mit dem Silan! Eine Reihe neuer chiraler Kupfer(I)‐Komplexe mit Bifluorid‐Gegenion wurde hergestellt und in den ersten enantioselektiven Silylgruppenübertragungen auf einen Aldehyd eingesetzt. Dieses Vorgehen führt schnell zu nichtracemischen α‐Hydroxysilanen in hohen Enantioselektivitäten.

Herein, we report the copper-catalyzed domino borylation/aldolisation of methyl 2-fluoroacrylate with carbonyl compounds followed by an elimination to give Morita-Baylis-Hillman (MBH) analogues. The optimal conditions described were shown to be compatible with a wide range of aldehydes and ketones. Unprecedented MBH adducts derived from ketones were efficiently synthesized.