- Catalyst-Controlled Stereoselective Barton–Kellogg Olefination
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Overcrowded alkenes are expeditiously prepared by the versatile Barton–Kellogg olefination and have remarkable applications as functional molecules owing to their unique stereochemical features. The induced stereodynamics thereby enable the controlled motion of molecular switches and motors, while the high configurational stability prevents undesired isomeric scrambling. Bistricyclic aromatic enes are prototypical overcrowded alkenes with outstanding stereochemical properties, but their stereocontrolled preparation was thus far only feasible in stereospecific reactions and with chiral auxiliaries. Herein we report that direct catalyst control is achieved by a stereoselective Barton–Kellogg olefination with enantio- and diastereocontrol for various bistricyclic aromatic enes. Using Rh2(S-PTAD)4 as catalyst, several diazo compounds were selectively coupled with a thioketone to give one of the four anti-folded overcrowded alkene stereoisomers upon reduction. Complete stereodivergence was reached by catalyst control in combination with distinct thiirane reductions to provide all four stereoisomers with e.r. values of up to 99:1. We envision that this strategy will enable the synthesis of topologically unique overcrowded alkenes for functional materials, catalysis, energy- and electron transfer, and bioactive compounds.
- Schmidt, Tanno A.,Sparr, Christof
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- THIOARYL SUBSTITUTED INHIBITORS OF ZINC PROTEASES AND THEIR USE
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There are described compounds having the general formula (I) below and their pharmaceutically acceptable salts thereof, wherein E, X, m, q, R1, R2, n and ZBG have the meanings reported in the description useful, in therapy, as inhibi
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Page/Page column 47
(2009/10/01)
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- Design, synthesis, biological evaluation, and NMR studies of a new series of arylsulfones as selective and potent matrix metalloproteinase-12 inhibitors
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Overexpression of macrophage elastase (MMP-12), a member of the matrix metalloproteinases family, can be linked to tissue remodeling and degradation in some inflammatory processes, such as chronic obstructive pulmonary disease (COPD), emphysema, rheumatoi
- Nuti, Elisa,Panelli, Laura,Casalini, Francesca,Avramova, Stanislava I.,Orlandini, Elisabetta,Santamaria, Salvatore,Nencetti, Susanna,Tuccinardi, Tiziano,Martinelli, Adriano,Cercignani, Giovanni,D'Amelio, Nicola,Maiocchi, Alessandro,Uggeri, Fulvio,Rossello, Armando
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experimental part
p. 6347 - 6361
(2010/03/24)
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- INHIBITORS OF ZINC PROTEASES THIOARYL SUBSTITUTED AND THEIR USE
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There are described compounds having the general formula (I) below and their pharmaceutically acceptable salts thereof, wherein E, X, m, q, R1, R2, n and ZBG have the meanings reported in the description useful, in therapy, as inhibi
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Page/Page column 74; 102-103
(2008/06/13)
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