Synthesis of the entire carbon framework of the kedarcidin chromophore aglycon

In advanced studies directed toward the total synthesis of the kedarcidin chromophore, we have successfully achieved the late-stage installation of the nine-membered diyne ring in the presence of the highly functionalised ansamacrocyclic bridge

Rapid Assembly of the Salvileucalin B Norcaradiene Core

Preparation of the polycyclic core of the cytotoxic natural product salvileucalin B is described. The key feature of this synthetic strategy is a copper-catalyzed intramolecular arene cyclopropanation to provide the central norcaradiene. These studies lay the foundation for continued investigations toward an enantioselective total synthesis of 1

Toward "Total Political History": A Rational-Choice Research Program

Political history is at an impasse. As the subjects of history expanded in the 1960s and 1970s, and as the prospects of societal change through political means dimmed in the 1980s, the study of war, diplomacy, and the writings and sayings of statemen--the principal raw materials of the old political history--lost favor with students and young professors alike. The organizing frameworks of politically centered history--Charles Beard's class analysis, Frederick Jackson Turner's stress on sectional splits, Louis Hartz's Lockeian consensus, Lee Benson's ethnoculturalism, and Walter Dean Burnham's critical-elections theory--have come under telling attack

Concise total synthesis of (+)-gliocladins B and C

The first total synthesis of (+)-gliocladin B is described. Our concise and enantioselective synthesis takes advantage of a new regioselective Friedel–Crafts-based strategy to provide an efficient multigram-scale access to the C3-(3′-indolyl)hexahydropyrroloindole substructure, a molecular foundation present in a significant subset of epipolythiodiketopiperazine natural alkaloids. Our first-generation solution to (+)-gliocladin B involved the stereoselective formation of (+)-12-deoxybionectin A, a plausible biosynthetic precursor. Our synthesis clarified the C15 stereochemistry of (+)-gliocladin B and allowed its full structure confirmation. Further studies of a versatile dihydroxylated diketopiperazine provided a concise and efficient synthesis of (+)-gliocladin B as well as access to (+)-gliocladin C.National Institute of General Medical Sciences (U.S.) (GM089732)Amgen Inc.National Science Foundation (U.S.) (CHE-0946721

Enantioselective Total Synthesis of (–)-Myrifabral A and B

A catalytic enantioselective approach to the Myrioneuron alkaloids (−)-myrifabral A and (−)-myrifabral B is described. The synthesis was enabled by a palladium-catalyzed enantioselective allylic alkylation, that generates the C(10) all-carbon quaternary center. A key N-acyl iminium ion cyclization forged the cyclohexane fused tricyclic core, while vinyl boronate cross metathesis and oxidation afforded the lactol ring of (−)-myrifabral A. Adaptation of previously reported conditions allowed for the conversion of (−)-myrifabral A to (−)-myrifabral B

Toward a New Phenomenon: Super-Cerenkov Radiation

In this letter a new coherent gamma emission mechanism, called Super-Cerenkov radiation, is introduced. The SCR is expected to take place when the charged particle is moving in a medium with a phase velocity satisfying the super-coherent condition. The results on an experimental test of SCR in RICH detector are presented.Comment: 5 pages, 2 figure

Toward "Total Political History"

How is the segmented and disoriented world of contemporary historical scholarship, in particular, that of American political history, to be reintegrated and revived? Instead of imposing a substantive synthesis, which would narrow the discipline's focus by excluding many interesting topics, I propose that historians adopt a common approach--rational choice theory--that has proven useful in economics and political science. Using notions drawn from rational choice and examples primarily from the American Civil War and Reconstruction period, I examine the assumptions behind and arguments for three theories in intellectual/cultural history--republicanism, "political culture," and positive/negative liberalism. I then try to spell out some of the implications of rational choice models for the study of electoral, legislative, judicial, and administrative behavior