Preparation and Double Michael Addition Reactions of a Synthetic Equivalent of the Nazarov Reagent

A synthetic equivalent of the Nazarov reagent, the silyl derivative <b>2</b>, able to undergo base-catalyzed double Michael addition reactions with α,β-unsaturated carbonyl compounds has been developed. The new reagent satisfactorily reacts with unsaturated indolo[2,3-<i>a</i>]quinolizidine lactams to give pentacyclic yohimbinone-type derivatives

Preparation and Double Michael Addition Reactions of a Synthetic Equivalent of the Nazarov Reagent

A synthetic equivalent of the Nazarov reagent, the silyl derivative <b>2</b>, able to undergo base-catalyzed double Michael addition reactions with α,β-unsaturated carbonyl compounds has been developed. The new reagent satisfactorily reacts with unsaturated indolo[2,3-<i>a</i>]quinolizidine lactams to give pentacyclic yohimbinone-type derivatives

Stereoselective Total Synthesis of the Putative Structure of Nitraraine

After the structure originally proposed for nitraraine was shown to be incorrect by total synthesis, the alternative structure <b>5</b> was recently suggested for the alkaloid on biosynthetic grounds and by comparison with the ¹H NMR data of tangutorine. The unambiguous synthesis of <b>5</b> is reported from tryptophanol and ketodiester <b>6</b>, via oxazoloquinolone lactam <b>7</b>. However, the melting point and ¹H NMR data of <b>5</b> did not match those reported for the natural product