Amphiphilic carbohydrate‐based mesogens, VII. Synthesis of mesogenic 4‐ and 6‐O‐alkyl‐D‐glucitols

Abstract

Both the hemiacetal and acetal groups of 4,6-O-alkylidene-2a -e. Subsequent deboronations give ca. 1 : 1 mixtures of a/P-D-glucopyranoses (hexylidenedecylidene, 1 ae) are 4-O-alkyl-~-glucitols 3 ae and 6-O-alkyl-~-glucitols 4ae, quantitatively reduced by ethyldiboranes(6) in the presence of which are separated to give mesogenic 3 and 4. Both 3 and 4 9-methylsulfonyloxy-9-borabicyclo[3.3.l]nonane (MSBBN) afexhibit smectic A liquid crystalline phases. ter conversion to their 1,2,3-tri-O-diethylboryl derivatives

Stereocontrol in Radical Processes through the Exocyclic Effect: Dual Role of Triethylboron as Radical Initiator and in Situ Derivatization Agent

“…The role of activating agents (e.g., pivalic acid, diethylborylpivalate) and full mechanistic details have yet to be delineated for reactions of alcohols with Et 3 B. Studies directed at better understanding the essential role of air in the diol series are presently underway …”