Golden opportunities in natural product synthesis: first total synthesis of (-)-isocyclocapitelline and (-)-isochrysotricine by gold-catalyzed allene cycloisomerization.

The first enantioselective total syntheses of the beta-carboline alkaloids (-)-isochrysotricine (1) and (-)-isocyclocapitelline (2) are reported which confirm the absolute configuration of these natural products. Key steps are the copper-mediated S(N)2'-substitution of propargyl oxiranes 13/14 and the gold-catalyzed cycloisomerization of alpha-hydroxyallene 15, resulting in a highly efficient center-to-axis-to-center chirality transfer.

Synthesis and SAR of novel 4,5-diarylimidazolines as potent P2X7 receptor antagonists.

A series of 4,5-diarylimidazoline libraries were prepared using high-throughput solid-phase and microwave techniques. The compounds were evaluated as P2X(7) antagonists and their SAR is described.