Total synthesis of (-)-4-desacetoxy-1-oxovindoline: Single atom exchange of an embedded core heteroatom in vindoline.

A concise total synthesis of (-)-4-desacetoxy-1-oxovindoline is disclosed, bearing a single heteroatom exchange in the core structure of the natural product 4-desacetoxyvindoline. Central to the synthesis is powerful oxadiazole intramolecular [4+2]/[3+2] cycloaddition cascade that formed four C-C bonds, created three new rings, and established five contiguous stereocenters about the new formed central 6-membered ring.

Biomimetic Aerobic C-H Olefination of Cyclic Enaminones at Room Temperature: Development toward the Synthesis of 1,3,5-Trisubstituted Benzenes.

A green and mild protocol for the dehydrogenative olefination of cyclic enaminones was devised via palladium catalysis at room temperature using oxygen as the terminal oxidant. The synthetic utility of the olefinated cyclic enaminones afforded a series of unique 1,3,5-trisubstituted benzenes via an unanticipated Diels-Alder tandem reaction. The broad substrate scope and good yields achieved with this new protocol provide an alternative pathway for arene functionalization.

Palladium-catalyzed direct C-H arylation of cyclic enaminones with aryl iodides.

A ligand-free method for the Pd-catalyzed direct arylation of cyclic enaminones using aryl iodides was developed. This method can be applied to a wide range of cyclic enaminones and aryl iodides with excellent C5-regioselectivity. Using widely available aryl iodides, the generality of this transformation provides easy access to a variety of 3-arylpiperidine structural motifs.

Dehydrogenative alkenylation of uracils via palladium-catalyzed regioselective C-H activation.

A regioselective Pd-catalyzed cross-dehydrogenative coupling between uracils and alkenes is reported. This protocol provides easy access to a variety of 5-alkenyluracil structural motifs.

Palladium(II)-catalyzed dehydrogenative alkenylation of cyclic enaminones via the Fujiwara-Moritani reaction.

A new Pd(II)-catalyzed dehydrogenative alkenylation reaction involving two alkenes was developed. A variety of nonaromatic, cyclic enaminones were successfully coupled to primary and secondary alkenes yielding a series of unique 1,3-dienes. The generality of this transformation presents a useful strategy for directly cross-coupling alkenes and offers an attractive new approach to functionalize enaminones.

Inhibition of methicillin-resistant Staphylococcus aureus by the compound Qingre granules.

Background: The infection rate of methicillin-resistant Staphylococcus aureus (MRSA) is increasing yearly due to the overprescription of antibiotics. Traditional Chinese compound medicines are less inclined to induce bacterial resistance in the clinical setting because of their multi-acting mechanisms. However, most current research is limited to bacteriostasis in vitro using single extracts or formulations.

Controlling regioselectivity in cyclization of unsaturated amidyl radicals: 5-exo versus 6-endo.

Intramolecular cyclization of an amidyl radical onto an olefin provides an appealing method for the synthesis of lactams and other nitrogen-containing heterocycles. Here we conducted the first, systematic theoretical study on the regioselectivity in the cyclization of various types of pent-4-enamidyl radicals that carried synthetically relevant substituents. It was found that the cyclization of most of the substituted pent-4-enamidyl radicals produced the 5-exo products (gamma-lactams) almost exclusively.