The first catalytic use of Ga(0) in organic synthesis has been developed by using a Ag(I) cocatalyst, crownether ligation, and ultrasonic activation. Ga(I)-catalyzed C–C bond formations between allyl or allenyl boronic esters and acetals, ketals, or aminals have proceeded in high yields with essentially complete regio- and chemoselectivity. NMR spectroscopic analyses have revealed novel transient Ga(I) catalytic species, formed in situ through partial oxidation of Ga(0) and B–Ga transmetalation, respectively. The possibility of asymmetric Ga(I) catalysis has been demonstrated.

In this review, more than 60 natural canthin-6-one alkaloids and their structures are considered. The biosynthesis, efficient and classic synthetic approaches, and biological activities of canthin-6-one alkaloids, from 1952 to 2015, are discussed. From an analysis of their structural properties and an investigation of the literature, possible future trends for canthin-6-one alkaloids are proposed. The information reported will be helpful in future research on canthin-6-one alkaloids.

An asymmetric aldehyde prenylation method assisted by a ( R )-BINOL-derived phosphoric acid [( R )-TRIP] catalyst for the total synthesis of (−)-rosiridol and (−)-bifurcadiol has been reported.