Stereoselective total synthesis of cryptomoscatone D1 and (5 R ,7 S )-kurzilactone via ring closing metathesis

Asymmetric total synthesis of cryptoconcatone I

Asymmetric total synthesis of the naturally occurring cryptoconcatone I, which possesses a γ-Z-butenolide framework, is described here for the first time. Asymmetric propargylation, E-selective cross metathesis, and regioselective reductive epoxide ring opening were employed to access the enantiopure terminal alkyne. Late stage bimetallic cascade cyclization of the alkyne with (Z)-3-bromoacrylic acid afforded the natural product in an efficient way.

Biosynthesis-Inspired Total Synthesis of Bioactive Styryllactones (+)-Goniodiol, (6S,7S,8S)-Goniodiol, (-)-Parvistone D, and (+)-Parvistone E

A protecting-group-free total synthesis of (+)-goniodiol (1), (6S,7S,8S)-goniodiol (2), (-)-parvistone D (4), and (+)-parvistone E (6) was efficiently achieved in five steps from commercially available trans-cinnamaldehyde with high overall yields (72-75%). The synthesis strategy was inspired from the proposed biosynthesis pathway of styryllactones. Key transformations of the strategy include a one-pot conversion of goniothalamin oxide to goniodiol or 9-deoxygoniopypyrone in aqueous media, stereoselective epoxidation, ring-closing metathesis, and stereoselective Maruoka allylation. The route is amenable to synthesis of various analogues for biological evaluation.