BINOL-based, chiral phosphoric acids catalyze the substitution of 1-(o-hydroxyphenyl)propargylic alcohols with enamides to furnish 7-alkynyl-12a-acetamido-substituted benzo[c]xanthenes and related heterocycles in a one-pot operation with excellent diastereo- and enantioselectivity. Ambient reaction temperature, operationally simple reaction conditions, low catalyst loading, high yields, and excellent stereocontrol are attractive features of this process and make it a highly practical and versatile transformation.

We disclose herein a highly enantioselective protocol for the Brønsted acid-catalyzed addition of indoles and phenols to in situ-generated ortho-quinone methides which deliver broadly substituted diarylindolylmethanes and triarylmethanes, respectively, in a one-pot reaction under very mild conditions. A chiral phosphoric acid catalyst has been developed for this process serving to convert the starting ortho-hydroxybenzhydryl alcohols into the reactive ortho-quinone methides and to control the enantioselectivity of the carbon-carbon bond-forming event via hydrogen-bonding.

Quinoxaline has become a subject of extensive research due to its emergence as an important chemical moiety possessing a wide range of physicochemical and biological activities. The last few decades...

Silver nanowires of diameter ∼40 nm and length ∼0.3 mm have been grown by electrodeposition within the pores of silica gels which were heat treated in the temperature range 523 to 823 K and, subsequently, soaked in a silver nitrate solution. A staircase current–voltage characteristic was observed in the direction of electrodeposition after nanowires were disrupted by the application of a dc voltage pulse. Such gels containing interrupted nanowires of silver showed a dielectric constant value ∼104 both in directions parallel and perpendicular to that of electrodeposition.