Organic reactions at alumina surfaces. An extremely simple, convenient and selective method for acetylating primary alcohols in the presence of secondary alcohols.

First Total Synthesis of the Sex Pheromone of the Oleander ScaleAspidiotus nerii: An Unusual Sesquiterpenic Functionalized Cyclobutane

“…Therefore, to optimize the formation of the hemiacetal, crude 29 was treated with SiO 2 in hexane to afford the unstable hemiacetal In an alternative approach compound 19 b was fully hydrolyzed with HCl/MeOH to afford dihydroxy ketone 31 in 90 % yield (Scheme 8). Then, regioselective acetylation of the primary alcohol was accomplished through a modification of the procedure described by Posner and Oda [57] (Al 2 O 3 W-200-N/AcOEt; 12 d, room temperature). Under these conditions acetate 32 was obtained in 60 % yield, along with 25 % of unreacted diol 31 which was recycled.…”

Selective Monoacetylation of Unsymmetrical Diols Catalyzed by Silica Gel-Supported Sodium Hydrogen Sulfate

“…Selective monoacetylation of unsymmetrical diols is an important procedure in organic synthesis as is reflected by the number of methods that have been developed to effect this transformation. , Acetylation via the process of transesterification employing heterogeneous catalysts is of particular convenience since starting esters (e.g., ethyl acetate) are readily available and the catalyst may be easily separated from the product mixture through simple filtration. 1c,, High selectivity for acetylation of primary hydroxyl group sites in the presence of secondary sites has been previously reported with the use of alumina as catalyst. 1c, This method suffers, however, from the large amounts of catalyst required (10 g of Al 2 O 3 /mmol of diol) as well as relatively high reaction temperatures (75−80 °C).…”

Low-level Free Phenols in Sicilian Olive Oils

“…Thus, 4-(acetoxyethyl)-1-hydroxybenzene can be synthesized according to the procedure of Posner and Oda (1981), and 3,4-dihydroxyphenylacetaldehyde can be synthesized according to the procedure of Fellman (1958) (Saitta et al, 2002).…”