Side chain type ionic liquid crystalline polymers having high Preliminary communication molecular weight

Side chain type ionic liquid crystalline polymers having a 4-(1,3-dioxan-2-yl)pyridinium structure in their mesogenic side chain were synthesized. These polymers exhibited the smectic A phase. The molecular weights of these ionic liquid crystalline polymers are very high, e.g. for compound 7 - 2 M _w = 486 000.     

A Synthesis of Exiguaquinol Dessulfate

A concise and stereoselective synthesis of exiguaquinol dessulfate is described. Sequential application of a Diels–Alder cycloaddition, a desymmetrizing aldol addition, and a reductive Heck cyclization established most of the architecture of exiguaquinol, and a carefully choreographed introduction of the polar substituents afforded the title compound; unfortunately, naphthoquinol sulfation could not be achieved to deliver exiguaquinol. Our hypothesis regarding the configurational preference of the N‐acyl hemiaminal, which was based upon an analysis of internal hydrogen‐bonding interactions with polar functional groups, was proven correct. A late‐stage intermediate did not demonstrate bactericidal activity against H. pylori cultures.     

Enantioconvergent Cross‐Couplings of Alkyl Electrophiles: The Catalytic Asymmetric Synthesis of Organosilanes

Metal‐catalyzed enantioconvergent cross‐coupling reactions of alkyl electrophiles are emerging as a powerful tool in asymmetric synthesis. To date, high enantioselectivity has been limited to couplings of electrophiles that bear a directing group or a proximal p/π orbital. Herein, we demonstrate for the first time that enantioconvergent cross‐couplings can be achieved with electrophiles that lack such features; specifically, we establish that a chiral nickel catalyst can accomplish Negishi reactions of racemic α‐halosilanes with alkylzinc reagents with good enantioselectivity under simple and mild conditions, thereby providing access to enantioenriched organosilanes, an important class of target molecules.