Oxa- and Azacycle Formation via Migrative Cyclization of Sulfonylalkynol and Sulfonylalkynamide with N-Heterocyclic Carbene

Remote electronic effect on the N-heterocyclic carbene-catalyzed asymmetric intramolecular Stetter reaction and structural revision of products

The remote electronic effects of chiral N-heterocyclic carbene catalysts on the asymmetric intramolecular Stetter reaction are investigated. The reaction rate and enantioselectivity were markedly influenced by a substituent at a remote position of the catalyst. The absolute configurations of the products are revised on the basis of X-ray diffraction. Density-functional theory calculations rationalize the improvement of the enantioselectivity using an electron-deficient catalyst.

Synthetic and mechanistic aspects of sulfonyl migrations

Sulfonyl migrations, frequently described as ‘unusual’ or ‘unexpected’, from the last 20 years, including 1,2-, 1,3-, 1,4-, 1,5-, 1,6- and 1,7-sulfonyl shifts, through either radical or polar processes, either inter- or intramolecularly are reviewed.

Site-selective benzoin-type cyclization of unsymmetrical dialdoses catalyzed by N-heterocyclic carbenes for divergent cyclitol synthesis

A highly site-selective NHC-catalyzed benzoin-type cyclization of unsymmetrical dialdoses was achieved.