Metal reductions of malonates and oxalates. A covenient decarboxylation route for disubstituted malonates and synthesis of keten acetals

The Chemistry of C-Nucleosides

“…There have been several reports dealing with electrophilic coupling reactions leading to derivatives of ribofuranosyl-benzene, (212)(213)(214) furan, (215) N-methylpyrrole, (216) thiophene, (214) and other carbocyclic compounds. (214,217) Little work has been accomplished for the application of these compounds to the synthesis of naturally occurring C-nucleosides and their analogues. (12,218) This section dealt with by far the most fruitful approach to date, i.e., the functionalization of a carbohydrate derivative at Col followed by the multistep elaboration of a heterocyclic base.…”

Silyl enol ethers and silyl ketene acetals

“…There are three main routes 53 to silyl ketene acetals. The first and most generally applicable of these mirrors one of the major routes to silyl enol ethers.…”

“…This rearrangement has been shown 53 to proceed intramolecularly via a four-membered transition state (139), and provides an excellent route to such ketenes, diphenylketene being produced in an overall yield of 80 per cent from methyl diphenylacetate (Scheme 17.137 Monoaryl or dialkyl substituted ketene acetals, on the other hand, give products of addition of the starting acetals to the initially produced ketenes. This rearrangement has been shown 53 to proceed intramolecularly via a four-membered transition state (139), and provides an excellent route to such ketenes, diphenylketene being produced in an overall yield of 80 per cent from methyl diphenylacetate (Scheme 17.137 Monoaryl or dialkyl substituted ketene acetals, on the other hand, give products of addition of the starting acetals to the initially produced ketenes.…”