Dynamic kinetic resolution during a vinylogous Payne rearrangement: a concise synthesis of the polar pharmacophoric subunit of (+)-scyphostatin.

The diastereomeric epoxycyclohexenols 3a/b (obtained via a Wharton rearrangement of a bis-epoxycyclohexanone precursor) were shown to undergo interconversion via a facile vinylogous Payne rearrangement. Mechanistic issues were probed; the doubly O-deuterated analogues underwent this equilibration more slowly than the parent dihydroxy compounds. It was possible to kinetically resolve the mixture of 3a/b under equilibrating conditions by use of Amano PS.

Okundoperoxide, a bicyclic cyclofarnesylsesquiterpene endoperoxide from Scleria striatinux with antiplasmodial activity.

Okundoperoxide (1) was isolated by bioassay-guided fractionation of extracts from Scleria striatinux (syn. S. striatonux).

Efficient synthesis of a GABA A alpha2,3-selective allosteric modulator via a sequential Pd-catalyzed cross-coupling approach.

A practical synthesis of 2-[3-(4-fluoro-3-pyridin-3-yl-phenyl)-imidazo[1,2-a]pyrimidin-7-yl]-propan-2-ol (1), an oral GABA(A) alpha(2/3)-selective agonist, is described. The five-step process, which afforded 1 in 40% overall yield, included imidazopyrimidine 2 and pyridine boronic acid 4 as key fragments. The synthesis is highlighted by consecutive Pd-catalyzed coupling steps to assemble the final free base 1 in high yield and regioselectivity.

Palladium-catalyzed regioselective arylation of imidazo[1,2-a]pyrimidine.

Imidazo[1,2-a]pyrimidine can be arylated at the 3-position with aryl bromides in the presence of base and a catalytic amount of palladium. This provides an efficient one-step synthesis of 3-arylimidazo[1,2-a]pyrimidines from the unsubstituted heterocycle. [reaction: see text]

An improved protocol for the preparation of 3-pyridyl- and some arylboronic acids.

3-Pyridylboronic acid was prepared in high yield and bulk quantity from 3-bromopyridine via a protocol of lithium-halogen exchange and "in situ quench". This technique was further studied and evaluated on other aryl halides in the preparation of arylboronic acids.