Reduction of carbonyl compounds promoted by silicon hydrides under the influence of trimethylsilyl-based reagents

Abstract

The synthetic utility of hydrosilanes under the influence of trimethylsilyl-based reagents as new reducing systems is described. 1,1,3,3-Tetramethyldisiloxane (TMDS) reagent in combination with iodotrimethylsilane or bromotrimethylsilane produces alkyl halides from aldehydes in good to excellent yields. Polymethylhydrosiloxane (PMS) in the presence of iodotrimethylsilane also produces benzyl iodides in excellent yields. On the contrary, PMS reagent was found unsuitable for the synthesis of benzyl bromides. Similarly, TMDS reagent in combination with trimethylsilyl triflate produces symmetrical ethers from aldehydes without concomitant formation of competitive products. Under similar conditions, PMS reagent failed to provide the expected symmetrical ethers and Friedel–Crafts products were formed. Reduction of quinones to hydroquinones is also described.

Kinetics and mechanism of the reaction of benzyl bromide with copper in hexamethylphosphoramide

“…The purities of the products were checked by elemental analysis and comparison of physical properties with those reported in the literature [5].…”

Oxidation of Benzylic Alcohols and Ethers to Carbonyl Derivatives by Nitric Acid in Dichloromethane

“…[35] 1,2-Diphenylethanol (4ff, 5.23 g, 88%) [36] was obtained from deoxybenzoin (2ff) in a similar way. [37] 1-(Iodomethyl)-2-nitrobenzene (59), [38] 1-(iodomethyl)-3-nitrobenzene (60), [39] and 1-(iodomethyl)-4-nitrobenzene (61) [40] were prepared in 88% (5.79 g), 77% (5.06 g), and 78% (5.13 g) isolated yields, respectively, by simply mixing of solutions of the corresponding chlorides in acetone (18.0 mmol in 4.0 mL) and NaI in the same solvent (18.0 mmol in 15.0 mL), by a described procedure. [41] The following alkyl and arylalkyl nitrites were prepared by a known general method: [20] hexyl nitrite (11,3.93 g, 60%), [42] phenylmethyl nitrite (16,4.93 g, 72%).…”

Polymethylhydrosiloxane

“…Unfortunately this solventless transformation does not work well with ketones or aliphatic aldehydes. 31 Fu and co-workers have shown that PMHS is instrumental in performing Barton-McCombie deoxygenations of thionocarbonates with only catalytic amounts of (Bu 3 Sn) 2 O (eq 17). 5 4 can be applied to reductive aminations (eq 21).…”