Synthesis of higher alicyclic compounds from thiophene derivatives

The synthesis of 3H-naphthol[1,8-bc]thiophene derivatives

“…Thiophenic compounds are difficult to reduce using conventional heterogeneous catalysts because of catalyst poisoning caused by adsorption of the sulfur to the active sites (23). In addition, high activity catalysts can desulfurize thiophenic systems.…”

The Acyloin Condensation as a Cyclization Method

“…Under similar conditions, but somewhat lowrer temperature, a linear acyloin containing two thiophene rings was obtained showing that the ring itself does not prevent reaction. Later work has increased the yields of systems containing a single thiophene ring by modifying the conditions and the substrate (56). The dimethyl-substituted compound in which the positions of the alkyl and ester groups is reversed has also been prepared by acyloin ring closure (56).…”

“…Later work has increased the yields of systems containing a single thiophene ring by modifying the conditions and the substrate (56). The dimethyl-substituted compound in which the positions of the alkyl and ester groups is reversed has also been prepared by acyloin ring closure (56). A very interesting start, which does not seem to have been followed, has been made in the application of the acyloin condensation to cyclization problems in the synthesis of steroids (see Table VI).…”

“…While the yields are low in most instances and no extensive variation of ring size has been made, the reaction does show some promise for future development. The improvement of the yield when the remaining thiophene positions are substituted with alkyl groups is remarkable (56).…”

Evaluating a Sodium Dispersion Reagent for the Bouveault–Blanc Reduction of Esters

“…Furthermore, the high temperature accelerates competitive base-promoted Claisen condensation and ester hydrolysis (Scheme A) . Reactions at lower temperature can be achieved by using the EtOH/NH 3 solvent system instead of EtOH or using NaK instead of the pure metal . These alternative protocols, however, are not general.…”