Direct Conversion of Acylsilanes to Esters Mediated by Iron (III) and Nitrate Ions

Acylsilanes and their applications in organic chemistry

“…The most common method for oxidation of acylsilanes utilizes peroxides but the electrochemical method, although seldom applied, appears to be advantageous because it permits the direct preparation of acids, esters or nitrogen derivatives, depending upon the additive present during electrolysis. Recently, we introduced a new method for direct esterification of alkyl and aroylsilanes by means of iron (III) ion or nitric acid oxidation in dilute alcohol solution (Scheme 44) 68 . 106 (7 6 -9 8 %) 104 (7 7 In this context, an important property of the acylsilanes is their oxidation through photoprocesses, affording compounds such as carboxylic acids (promoted by room light) 69,70 or silylesters 112 and viniloxysilanes 114 as principal products (Scheme 45) 71 .…”

A Mechanistic Study concerning the Carbon-Silicon Bond Cleavage in Acylsilane Bioreductions

“…The oxidation of acylsilanes to carboxylic acids is well known to occur by light activation, high temperatures 14 and by treatment with peroxide, 15 ozone 16 and Fe(NO) 3 . 17 Table 2 also shows that aldehyde yields were not decreased by the presence of radical inhibitors. Therefore, the aldehyde probably is produced by a mechanism that does not involve radical formation.…”

“…In fact, the aldehyde formation was observed when acylsilanes were treated with aqueous solutions of Fe(NO 3 ) 3 and Al 2 (SO 4 ) 3 but not with H 2 SO 4 or HNO 3 . 17 In contrast to acylsilane cleavage by fluoride ion, 20 it is possible that this mechanism occurs without arylcarbanion formation, because the cleavage ratio didn't diminish with the aromatic ring having a methoxy as substitute group.…”

Generally applicable and efficient esterification of aldehydes with alcohols catalyzed by cyclopalladated ferrocenylimine

“…The products 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h , 3i , 3k , 3l , 3m , 3n , 3o , 3p , 3q , 3r , 3s , 3t , 3u , 3v , 3w , 3x , 3y , 3z , 3δ and 3φ were characterized by comparing their 1 H NMR and 13 C NMR spectra with those mentioned in the references.…”