Synthesis and Structure ofN-(Silylalkyl)amides:  Rhodium-Catalyzed Hydrosilylation of Enamides

Abstract

Rh(II) acetate effectively catalyzed the hydrosilylation of enamides, N-vinylurea, and imides to give N-(silylalkyl)amide derivatives in moderate to high yields. The silyl group was selectively introduced to the carbon atom adjacent to the nitrogen atom, whereas the efficiency and regioselectivity of the Rh-catalyzed hydrosilylation of vinyl carboxylates, thiocarboxylates, ethers, and thioethers were highly affected by the substitution patterns of the substrates and reaction conditions. The reaction of N-vinylphthalimide (1f) with deuteriosilane suggests that the catalytic process involving the oxidative addition of hydrosilane and migratory insertion of the alkenyl group of 1f is reversible. The molecular structures of the N-(1-silylethyl)phthalimide 2f and N-(1-silylethyl)acetamide 2k species have been determined by X-ray analyses. The results show that there is no intramolecular interaction between the silicon atom and the oxygen atom of the carbonyl groups of 2f and 2k.

2-{[(4-Methoxyphenyl)dimethylsilyl]methyl}isoindoline-1,3-dione

“…Torsion angles C(11/18)-N1-C10-Si1 involving the silyl group are 90.5 (2) and -93.1 (2)°, similar to those in the related compound 6-(phthalimidomethyl(dimethyl)silyl)hexan-1-ol (Latxague & Leger, 2004). This is an indication that there is no interaction between the carbonyl oxygen and the silicon atom despite silicon's high affinity for oxygen (Murai et al, 1998).…”

Markovnikov Alkyne Hydrosilylation Catalyzed by Ruthenium Complexes

“…Some of these afford good control of olefin geometry . The limited number of known hydrosilylations with ruthenium catalysts give the analogous linear products. , Free alcohols 10 and carbonyl groups have been shown to direct hydrosilylation to provide internal silanes, presumably through coordination. However, to our knowledge, there are no published reports of nondirected terminal alkyne hydrosilylation to afford preferentially the internal vinylsilane.…”

Silanediol Protease Inhibitors: From Conception to Validation

“…For preparation of the α‐amino silane component, several synthetic methods were investigated, three of which were summarized in Scheme . Hydrosilylation is one of the most important methods for silicon–carbon bond formation,71–73 and hydrosilylation of N ‐alkenyl amides such as 82 , Scheme , had been been the subject of several reports 74,75. Alternatively, alkylation of an anion between silicon and nitrogen in 84 was studied, an anion that would profit from stabilization by the silicon76 and could be prepared using the metalation‐directing capacity of the Boc group 77.…”

“…Curtius rearrangement of acyl azides derived from acrylic acids 86 , Scheme , provides a general route to Boc‐derivatized vinylamines 82 78. Rhodium‐catalyzed hydrosilylation has been found to provide the desired regioselectivity 74,75. In these studies, triethylsilane gave the highest yields for this reaction, but a diphenylsilyl group was required as a precursor to the silanediols.…”