Dormant versus evolving aminopalladated intermediates: toward a unified mechanistic scenario in Pd(II)-catalyzed aminations.

Pd(II)-catalyzed alkene aminopalladation and allylic C-H activation are two competing reaction sequences sharing the same reaction conditions. This study aimed at understanding the factors that bias one or the other path in the intramolecular oxidative cyclization of two types of N-tosyl amidoalkenes. The results obtained are in accord with the initial generation of a high-energy cyclic (5- or 6-membered) aminopalladated intermediate.

Study of the total synthesis of (-)-exiguolide.

In this article, we disclose the various routes and strategies we had to explore before finally achieving the total synthesis of (-)-exiguolide ((-)-1). Two first types of approaches were set, both relying on the Trost's domino ene-yne coupling/oxa-Michael reaction that we choose for its ability to control the geometry of the methylacrylate-bearing tetrahydropyrane ring B. In our first approach, we expected to assemble the two main fragments (C14-C21 and C1-C13) by creating the C13-C14 bond through a palladium(0)-catalyzed cross-coupling, but this step failed, unfortunately.

Pd-catalyzed domino carbonylative-decarboxylative allylation: an easy and selective monoallylation of ketones.

In the presence of an allyl alcohol, α-chloroacetophenones undergo an allyloxycarbonylation reaction followed by in situ decarboxylative allylation to selectively afford the corresponding monoallylated ketones via a Pd-catalyzed domino sequence. The scope of the reaction was extended to substituted α-chloroacetophenones as well as various allyl alcohols.

Total synthesis of (-)-exiguolide.

The first total synthesis of the naturally occurring enantiomer of exiguolide ((-)-1) has been completed. This very convergent synthesis features the following as main steps: (i) a Trost's ruthenium-catalyzed ene-yne cross-coupling reaction (this complex transformation allows the challenging control of the C5-C28 double bond geometry along with the stereoselective construction of the tetrahydropyran ring A) and (ii) a very efficient one-pot, two-step stereoselective conjugated allylic alcohol substitution that allowed the control of the C15 stereogenic center.

A new cross-coupling-based synthesis of carpanone.

Carpanone has been stereoselectively synthesized in 55% yield and six steps from sesamol. The key step of the synthetic sequence is the direct introduction of the propenyl side chain via a Suzuki-Miyaura cross-coupling reaction. The subsequent Pd(II)-catalyzed oxidative coupling yields carpanone as a single diastereoisomer independently of the geometric configuration of the starting precursor.

An antiplasmodial new (bis)indole alkaloid from the hard coral Tubastraea sp.

Tubastarea sp., a stony coral (Dendrophylliidae) from the Great Hanish in the Archipelago of the Hanish Islands, Yemen, contains, in addition to the known aplysinopsin (1) and 6-bromo-3'-deimino-3'-oxoaplysinopsin (2), the new bis(indole) alkaloid (3). The structures of compounds (1-3) were elucidated by interpretation of spectral data.

Suzuki-miyaura cross-coupling of 1,1-dichloro-1-alkenes with 9-alkyl-9-BBN.

We addressed an unexplored application of the Suzuki-Miyaura protocol to the cross-coupling of 1,1-dichloro-1-alkenes with 9-alkyl-9-BBN. The use of bisphosphine ligands with a large P-Pd-P bite angle allowed us to synthesize Z-chlorinated internal alkenes in good yields resulting from a selective monocoupling process, a recurrent challenge with 1,1-dichloro-1-alkenes. Moreover, these monochlorinated olefins could be further transformed providing stereospecifically trisubstituted olefins.

Evaluation of the AxSYM monoclonal cyclosporin assay and comparison with radioimmunoassay.

Recently, a semiautomated fluorescence polarization immunoassay (FPIA) for determination of parent cyclosporin (CsA) has been developed for the Abbott AxSYM system. The new CsA assay measures the drug from an extracted whole blood specimen. The authors report here the evaluation of this new assay and the comparison with a previously validated radioimmunoassay (RIA) method (CYCLO-Trac SP).

Evaluation of circulating type I procollagen propeptides in patients with Paget's disease of bone.

We evaluated circulating aminoterminal and carboxyterminal propeptides of type I procollagen and total alkaline phosphatase levels in eighty consecutive patients affected by Paget's disease of bone. We compared the biochemical data with the extent of bone disease calculated on the basis of the bone scintigraphic indices. Serum aminoterminal propeptide of type I procollagen levels were high in 77% of patients, serum carboxyterminal propeptide of type I procollagen levels in 22% and serum total alkaline phosphatase levels in 76%.

Platelet [3H]imipramine and [3H]paroxetine binding in depressed patients.

[3H]Paroxetine and [3H]imipramine binding to blood platelet membranes was simultaneously measured in 63 control subjects and 18 patients with DSM-III-R criteria for major depression with melancholia. Both binding sites showed significantly different (p < 0.001) maximum binding (Bmax) and equilibrium dissociation constant (Kd) values.