This study was aimed at determining the effect, if any, that steric factors may have on the diastereoselectivity in the spiroannulation of simple phenols. A series of phenols bearing different size substituents ortho to the phenolic hydroxyl were synthesized and spiroannulated to the corresponding spiroethers in good to excellent yields (76-94%). However, the diastereoselectivity of the reactio...

Eeny, meeny, miny ... enaminones! Lactams and imides have been shown to consistently provide enantioselectivities substantially higher than other substrate classes previously investigated in the palladium-catalyzed asymmetric decarboxylative allylic alkylation. Several new substrates have been designed to probe the contributions of electronic, steric, and stereoelectronic factors that distingui...

A new stereoelectronic theory for the cleavage of the tetrahedral intermediate in the hydrolysis of esters and amides is presented. In this new theory, the precise conformation of the intermediate hemi-orthoester or hemi-orthoamide controls the nature of the hydrolysis products. It is postulated that the breakdown of a conformer of a tetrahedral intermediate depends upon the orientation of the ...

The preparation of a 1,3-bis(2,6-terphenyl)imidazol-2-ylidene, IDitop (Ditop=2,6-bis(4-tolyl)phenyl-) is reported. Several late transition metal complexes as well the selenium adduct were prepared to study and compare stereoelectronic properties other well-known N-heterocyclic carbenes (NHCs). A steric character taken from crystal structure data adducts reveals high degree flexibility. Prelimin...

Tuberculosis, aggravated by drug-resistant strains and HIV co-infection of the causative agent Mycobacterium tuberculosis, is a global problem that affects millions of people. With essential immunoregulatory roles, phosphatidylinositol mannosides are among the cell-envelope components critical to the pathogenesis and survival of M. tuberculosis inside its host. Here we report the first synthesi...

We introduce a previously unexplored parameter-halenium affinity (HalA)- as a quantitative descriptor of the bond strengths of various functional groups to halenium ions. The HalA scale ranks potential halenium ion acceptors based on their ability to stabilize a "free halenium ion". Alkenes in particular but other Lewis bases as well, such as amines, amides, carbonyls, and ether oxygen atoms, e...

2'-Deoxy-2'-fluoro-arabinonucleic acid (FANA) and arabinonucleic acid (ANA) paired to RNA are substrates of RNase H. The conformation of the natural DNA/RNA hybrid substrates appears to be neither A-form nor B-form. Consistent with this, the conformations of FANA and ANA were found to be intermediate between the A- and B-forms. However, FANA opposite RNA is preferred by RNase H over ANA, and th...

The relative energies of side-on versus end-on binding of molecular oxygen to a supported Cu(I) species, and the singlet versus triplet nature of the ground electronic state, are sensitive to the nature of the supporting ligands and, in particular, depend upon their geometric arrangement relative to the O2 binding site. Highly correlated ab initio and density functional theory electronic struct...