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The application of dirhodium(II) caprolactamate as an efficient engine for the production of the tert-butylperoxy radical and selective reagent for hydrogen atom abstraction is demonstrated. The mechanistic implications arising from studies of allylic oxidation with enones provide new insights into factors that control product formation.

The selective C-H oxidation of alkynes to propargylic ketones was performed by using dirhohdium caprolactamate ([Rh.sub.2][(cap).sub.4]) with 70 percent w/w aqueous tert-butyl hydroperoxide as a highly effective catalytic oxidation protocol. The oxidation in aqueous solvent under mild condition with yields about 80 percent of [alpha],[beta]-acetylenic carbonyl compounds was found.

The article presents guidelines for college teachers to teach organic chemistry in the U.S. These guidelines include inquiring about the internal support available for teachers at an institution, regular performance assessments of full-time, tenure-track teachers, and writing a proposal for research support. It provides information on the traditional curriculums for chemistry courses, student recruitment and mentoring, and professional ethics.

Dirhodium(II) caprolactamate (1, Rh2(cap)4) with 70% w/w aqueous tert-butyl hydroperoxide (T-HYDRO) is a highly effective catalytic oxidation protocol for the selective C-H oxidation of alkynes to propargylic ketones. The oxidation occurs readily in aqueous solvent under mild conditions with an inexpensive and easily handled oxidant. α,β-Acetylenic carbonyl compounds are formed in up to 80% isolated yield. [ABSTRACT FROM AUTHOR]

A microwave-mediated aziridination of α,β-unsaturated ketones and esters through the decomposition of ethyl azidoformate is developed. [ABSTRACT FROM AUTHOR]

Ligand recognition in purine riboswitches is a complex process requiring different levels of conformational changes. Recent efforts in the area of purine riboswitch research have focused on ligand analogue binding studies. In the case of the guanine xanthine phosphoribosyl transferase (xpt) riboswitch, synthetic analogues that resemble guanine have the potential to tightly bind and subsequently influence the genetic expression of xpt mRNA in prokaryotes. We have carried out 25 ns Molecular Dynamics (MD) simulation studies of the aptamer domain of the xpt G-riboswitch in four different states: guanine riboswitch in free form, riboswitch bound with its cognate ligand guanine, and with two guanine analogues SJ1 and SJ2. Our work reveals novel interactions of SJ1 and SJ2 ligands with the binding core residues of the riboswitch. The ligands proposed in this work bind to the riboswitch with greater overall stability and lower root mean square deviations and fluctuations compared to guanine ligand. Reporter gene assay data demonstrate that the ligand analogues, upon binding to the RNA, lower the genetic expression of the guanine riboswitch. Our work has important implications for future ligand design and binding studies in the exciting field of riboswitches.

[Reaction: see text] Intramolecular photocycloaddition of 4 leads to the formation of cyclobutene photoadduct 5. Secondary photoreaction of 5 then affords either cyclobutane 19 or the bridged product 7, as a function of R (H or TMS).

[reaction: see text] A synthesis of 28, the carbon framework of the eleutherobin aglycone, is reported in a 15-step sequence from readily available starting materials. The tandem Diels-Alder reaction of 6 and 7 to produce 18, in which three new rings and six new stereocenters are formed, is a key step in the reaction sequence.