Toluenesulfonate esters , synthesis from alcohols

A recent synthesis of the tricyclic secoiridoid ( )-sarracenin (98) relied on the Patemo-Biichi addition of acetaldehyde and cyclopentadiene as the initial step. Irradiation of cyclopentadiene and acetaldehyde provided a 5 1 mixture of bicyclic oxetanes (97) and (96) in 5-10% yield. Treatment of the crude photolysate with CSA and methanol followed by tosylation of the cmde product gave (99), which represents the toluenesulfonate ester derived from the major oxetane (97). The tosylate was displaced by the anion prepared from dimethyl 3-styrenylmalonate to afford the substituted malonate (100) in 84% yield (Scheme 10). Attempts to effect ring opening of the oxetane mixture were unsuccessful. Decarboxylation and demethylation gave the alcohol (102) which was subjected to ozonolysis and reductive work-up to afford ( )-sarracenin in 60% yield. The oxetane-based synthesis is noteworthy due to its brevity and use of a biosynthetically postulated trialdehyde equivalent. 

Acrylic Esters. A procedure has been described for preparation of higher esters from methyl acrylate that illustrates the use of an acid catalyst together with the removal of one of the products by azeotropic distillation (112). Another procedure for the preparation of butyl acrylate, secondary alkyl acrylates, and hydroxyalkyl acrylates using -toluenesulfonic acid as a catalyst has been described (113). Alurninumisopropoxide catalyzes the reaction of amino alcohols with methyl acrylate and methyl methacrylate. A review of the synthesis of acryhc esters by transesterification is given in Reference 114 (see... 

Ether linkages in open-chain bolaamphiphiles were obtained in a 20% isolated yield from a,o)-dibromoeicosane with an alcohol in THF containing sodium hydride (Scheme 2.8). The synthesis of macrocyclic tetraethers was unsuccessful. Attempts to reduce macrocyclic lactones with four ester groups via a variety of methods failed. The production of macrocyclic thioacetals from benzaldehyde derivatives and a,to-dithiols was unproblematic and produced quantitative yields (Scheme 2.8). The cyclization of 2,2-thiodiethanol with a,(o-diols in the melt and in the presence of /7-toluenesulfonic acid is an intermediate case. Apolar macrocycles were obtained in 50% yield. 5-(2-hydroxyethyl)thiiranium ions are presumably formed as reactive intermediates during the ether formation steps. The sulphur atom was oxidized to the... 

Cirin-Novta et al. (2006) have carried out the synthesis of esters of natural petroleum acids of the naphthenic type in presence of microwave irradiation under the conditions of acid catalysis with various alcohols like methanol, ethanol, -butanol and tert-butyl alcohol. The esters of the naphthenic acid were prepared imder microwaves irradiation by using naphthenic acids with sulfuric and /7-toluenesulfonic acid. The yield of naphthenic esters from 31.25 to 88.90% was achieved, which was dependent on the catalyst and the steric and nucleophilic properties of the alcohols. It was also found that the esterification time was reduced from 6-10 h to 5 min in microwaves. 

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