Total Synthesis of Marine Natural Products (+)-Strongylin A and Corallidictyal D by Regio- and Stereoselective Cyclization of Alkenyl Benzenes.

An expeditious access to marine natural products (+)-strongylin A and corallidictyal D is described. A TFA/EtSiH-induced reductive isomerization of enols to alkenyl benzenes followed by a selectivity-controlled cyclization in the presence of HCl and BF·EtO affords benzofuran and benzopyran , respectively. The applicability of this HCl-induced cyclization is showcased by a regio- and stereoselective synthesis of corallidictyal D, while BF·EtO-promoted cyclization posterior to rearrangement of an alkenyl benzene provides a regioselectively different benzopyran, (+)-strongylin A.

Concise synthesis of marine natural products smenodiol and (-)-pelorol.

A facile synthesis of marine natural product smenodiol has been achieved in 23.2% overall yield within 8 steps from readily available starting materials, which facilitates a concise synthesis of the marine natural product (-)-pelorol by employing a TMSOTf-mediated Friedel-Crafts reaction with a methyl ester in the aryl as the key step.

A concise synthesis of marine natural product (-)-15-oxopuupehenol from (+)-sclarelide.

A step-economical synthesis of (-)-15-oxopuupehenol from cheap and readily available (+)-sclarelide is achieved with 20.3% overall yield in 9 steps. The key features of this synthetic mythology include a palladium catalyzed tandem carbine migratory insertion reaction to construct the key skeleton, a DDQ-mediated isomerization/oxidation of allyl alcohol to afford α, β-unsaturated ketone, and a NaOH-induced intramolecular Michael addition followed by acetonide deprotection to give (-)-15-oxopuupehenol.

Direct C2-arylation of -acyl pyrroles with aryl halides under palladium catalysis.

C2-arylation of N-acyl pyrroles with aryl halides is developed for the first time using Pd(PPh3)4 as a catalyst in combination with Ag2CO3 under air, which allowed the application of a good compatibility catalytic system. This protocol provides a straightforward method for the preparation of valuable arylated pyrroles in moderate to good yields under the standard conditions with good substrate tolerance. Interestingly, while N-benzoyl pyrroles reacted well, the use of substrates with a thiophene or furan ring indicated that the thiophene and furan rings are more reactive than pyrrole for the present catalytic system.

Synthesis of natural product inulavosin via Ga(OTf)-Catalyzed Hetero Diels-Alder Dimerization of salicyl alcohol derivative.

Inulavosin, a natural melanogenesis inhibitor, has been synthesized smoothly from readily available and inexpensive starting materials by using a Ga(OTf)-catalyzed room temperature hetero Diels-Alder dimerization of salicyl alcohol derivative and a regioselective phenol monobromination as the key steps.

Relationship between Intrauterine Bacterial Infection and Early Embryonic Developmental Arrest.

Background: Early embryonic developmental arrest is the most commonly understudied adverse outcome of pregnancy. The relevance of intrauterine infection to spontaneous embryonic death is rarely studied and remains unclear. This study aimed to investigate the relationship between intrauterine bacterial infection and early embryonic developmental arrest.