Stereoselective synthesis of methyl (1R) - and (1R) -hemicaronaldehydes from natural tartaric acid: Application to the synthesis of s-bioallethrin and deltamethrin insecticides§

Total synthesis of (+)-phomopsolide C by ring-size selective ring-closing metathesis/cross-metathesis

[reaction: see text]A new strategy for the synthesis of chiral 6-substituted 5,6-dihydro-5-hydroxypyran-2-ones by ring-size selective ring-closing metathesis (RCM) and its application to a short total synthesis of (+)-phomopsolide C are described. The key bond-forming reactions in this approach are a chemoselective cross-metathesis (CM) and RCM.

Novel ketal ligands for the glucocorticoid receptor: in vitro and in vivo activity

A novel series of selective ligands for the human glucocorticoid receptor is described. Structure-activity studies focused on variation of B-ring size, ketal ring size, and ketal substitution. These analogs were found to be potent and selective ligands for GR and have partial agonist profiles in functional assays for transactivation (TAT, GS) and transrepression (IL-6). Of these compounds, 27, 28, and 35 were evaluated further in a mouse LPS-induced TNF-alpha secretion model. Compound 28 had an ED(50) of 14.1 mg/kg compared with 0.5 mg/kg for prednisolone in the same assay.

Stereocontrol in Diels-Alder cycloaddition to unsaturated sugars: reactivities of acyclic seven-carbon trans dienophiles derived from aldopentoses

Acyclic trans-2,3-unsaturated aldoheptonate derivatives (1-9) obtained from D-aldopentoses by Wittig chain-extension served as dienophiles for a detailed comparative study of their asymmetric Diels-Alder cycloaddition with cyclopentadiene. Cycloaddition under uncatalyzed thermal conditions gave mixtures of the four possible stereoisomeric norbornene adducts. The endo:exo ratios and the diastereofacial selectivities in the formation of the adducts were determined by NMR spectroscopy and by chemical transformations. The quantitative distribution of adducts as a function of stereochemistry of the dienophile is discussed.