Ketene-S,N-acetals as synthetic intermediates for heterocycles. Reaction of ketene-S,N-acetals with aryl isocyanates.

Gallium tribromide catalyzed coupling reaction of alkenyl ethers with ketene silyl acetals.

Carbogallation of alkynes using gallium tribromide and silyl ketene acetals and synthetic application to cross-coupling with aryl iodides.

Enantioselective acylation of silyl ketene acetals through fluoride anion-binding catalysis.

A highly enantioselective acylation of silyl ketene acetals with acyl fluorides has been developed to generate useful α,α-disubstituted butyrolactone products. This transformation is promoted by a new thiourea catalyst and 4-pyrrolidinopyridine and represents the first example of enantioselective thiourea anion-binding catalysis with fluoride.

Cycloaddition of Azosulfones and Sulfonylimines

Ketene N,N-acetals ( I ) and ketene 0,N-acetals (2) containing hydrogen in the 2-position afford P-substitution products when treated with compounds such as isocyanates and isothiocyanates that contain an electrophilic double bond system[l~zl. However, azosulfones (3) [31 and N-sulfonylimines (7) [41 react with ketene N,N-acetals ( I ) by cycloaddition, affording the hitherto unknown 1,2-dihydr...

Copper-mediated intramolecular oxidative C-H/C-H cross-coupling of α-oxo ketene N,S-acetals for indole synthesis.

CuCl2-mediated intramolecular C-H/C-H cross-dehydrogenative coupling (CDC) of thioalkyl-substituted α-acetyl or α-aroyl ketene N,S-acetals afforded 2-thioalkyl indoles. Tunable C-S bond transformations of the resultant indoles led to highly functionalized N-heterocyclic compounds. A β-thioalkyl is necessary to activate the N,S-acetal substrate and enable the CDC reaction to occur, and the relev...