Synthesis of exo-methylenedifluorocyclopentanes as precursors of fluorinated carbasugars by 5-exo-dig radical cyclization

A practical synthesis of nitrone-derived C5a-functionalized isofagomines as protein stabilizers to treat Gaucher disease

Isofagomine (IFG) and its analogues possess promising glycosidase inhibitory activities. However, a flexible synthetic strategy toward both C5a-functionalized IFGs remains to be explored. Here we show a practical synthesis of C5a-S and R aminomethyl IFG-based derivatives via the diastereoselective addition of cyanide to cyclic nitrone 1. Nitrone 1 was conveniently prepared on a gram scale and in high yield from inexpensive (-)-diethyl D-tartrate via a straightforward method, with a stereoselective Michael addition of a nitroolefin and a Nef reaction as key steps. A 268-membered library (134 × 2) of the C5a-functionalized derivatives was submitted to enzyme- or cell-based bio-evaluations, which resulted in the identification of a promising β-glucocerebrosidase (GCase) stabilizer demonstrating a 2.7-fold enhancement at 25 nM in p.Asn370Ser GCase activity and a 13-fold increase at 1 μM in recombinant human GCase activity in Gaucher cell lines.

First stereoselective total synthesis of brevipolide M

The first stereoselective total synthesis of a cytotoxic brevipolide M, which shares a pyrone framework bearing a tetrahydrofuran moiety and a cinnamate group with the readily available (-)-DET, is described. The key steps involved in the synthesis are the epoxide-opening, Brown's allylation, and the RCM reaction to install an α,β-unsaturated lactone ring and the inversion of the C-6' stereogenic hydroxyl group using the Mitsunobu reaction.

Synthesis of Natural Products and the Development of Synthetic Methodology: The Case Study of (–)-Atrop-abyssomicin C

During our attempt to follow the planned synthetic route to the naturally occurring antibiotic (–)- atrop-abyssomicin C, we encountered two shortcomings, which forced us to reconsider our tactics and find new methods to overcome the problems. These methods turned out to be of general applicability, as demonstrated later in total syntheses of two other natural products: (+)-allokainic acid and (-)-gabosine H. The paper provides a brief account of these endeavors.