Synthesis of α- and β-Carbolines by a Metalation/Negishi Cross- Coupling/SNAr Reaction Sequence

A methodology for the synthesis of α- and β-carbolines from fluoropyridines and 2-haloanilines is reported. This procedure consists of a four-step directed ortho-lithiation, zincation, Negishi cross-coupling, and intramolecular nucleophilic aromatic substitution, providing access to a diverse set of functionalized carbolines. While the procedure is applicable to batch conditions, the generation of arylzinc intermediates in continuous flow has been demonstrated

Быстродействующая система стабилизации переменного напряжения

Рассматривается система стабилизации переменного напряжения на основе магнитно-полупроводникового регулятора без подмагничивания постоянным током и быстродействующей обратной связи. По описанному принципу могут быть построены быстродействующие однофазные и трехфазные стабилизаторы напряжения на встречно-параллельных управляемых вентилях при их естественной или принудительной коммутации

Singing Actors and Dancing Singers

This article looks at two recent and widely recognized productions of Henry Purcell's Dido and Aeneas (by choreographer Sasha Waltz, Berlin 2005, and theatre director Sebastian Nübling, Basel 2006) and discusses three main aspects: 1. Genre: coming from a Tanztheater (Waltz) and a Sprechtheater (Nübling) background, each director renegotiates conventions of the operatic genre and consciously evades expectations in pursuit of a new and challenging experience for both the performers and their audience. 2. Physicality: both productions place the performers' bodies at the forefront of the mise-en-scne they remap the singing, dancing, acting body by questioning conventions and expectations commonly found in the production and reception process. 3. Adaptation: both productions take unconventional liberties by adapting in a domain where notions of Werktreue (fidelity to the original work or score) still reign. Adopting ideas from Nicholas Cook and Mikhail Bakhtin, I will argue that the conceptual, musical and theatrical implications of both productions indicate a renegotiation of the social and performative relevance of operatic performance

Continuous-Flow Synthesis of Biaryls by Negishi Cross-Coupling of Fluoro- and Trifluoromethyl-Substituted (Hetero)arenes

A continuous-flow method for the regioselective arylation of fluoroarenes and fluoropyridines has been developed. The telescoped procedure reported here consists of a three-step metalation, zincation, and Negishi cross-coupling sequence, providing efficient access to a variety of functionalized 2-fluorobiaryl products. Precise temperature control of the metalation step, made possible by continuous-flow technology, allowed for the efficient preparation of the arylated products in high yields and short residence times. Additionally, several examples of the regioselective arylation of benzotrifluoride derivatives are also provided

Short Enantioselective Total Synthesis of Tatanan A and 3-epi-Tatanan A Using Assembly-Line Synthesis

Short and highly stereoselective total syntheses of the sesquilignan natural product tatanan A and its C3 epimer are described. An assembly-line synthesis approach, using iterative lithiation–borylation reactions, was applied to install the three contiguous stereocenters with high enantio- and diastereoselectivity. One of the stereocenters was installed using a configurationally labile lithiated primary benzyl benzoate, resulting in high levels of substrate-controlled (undesired) diastereoselectivity. However, reversal of selectivity was achieved by using a novel diastereoselective Matteson homologation. Stereospecific alkynylation of a hindered secondary benzylic boronic ester enabled completion of the synthesis in a total of eight steps

Stereoselective synthesis of (R)- and (S)-1,2-diazetidine-3-carboxylic acid derivatives for peptidomimetics

The stereoselective synthesis of both enantiomers of N-protected 1,2-diazetidine-3-carboxylic acid (aAze) from homochiral glycidol is described. Orthogonal protection of this novel cyclic α-hydrazino acid allows for selective functionalisation at either Nγ or Nδ. This novel peptidomimetic building block was incorporated into the pseudotripeptides Gly-γaAze-Ala and Gly-δaAze-Ala