Synthesis of bicyclic alcohols by palladium-catalyzed Et2Zn-mediated intramolecular carbonylpropargylation

Abstract

Propargylic esters derived from cyclic ketones containing a tethered aldehyde generate bicyclic homopropargyl alcohols upon treatment with Et2Zn in the presence of a catalytic amount of Pd(0). The reaction is thought to involve an intramolecular carbonyl addition of intermediate allenylzinc nucleophilic species generated from the propargylic ester functionality. The resulting trisubstituted bicyclic products are obtained with high stereoselectivity. Examples are provided where the reaction is successfully applied to both cyclopentanone-and cyclohexanone-derived substrates containing either terminal or internal alkyne, thus overcoming some of the limitations previously encountered with the use of alternative methodology.

Extension of the GROMOS 56a6CARBO/CARBO_R Force Field for Charged, Protonated, and Esterified Uronates

“…The non-GROMOS carbohydrate-dedicated force fields applied to simulate the uronate molecules include: AMBER14, GLYCAM06 (with the extensions proposed by Dentini et al or Hackbusch et al), CHARMM, OPLS-AA, CVFF, and (CHARMM-based) CSFF . The main field of their application is connected mainly with investigating the structural and conformational properties of naturally occurring mono- (e.g., iduronic acid and its derivatives) and polyuronates (e.g., alginates or pectins) as well as their interactions with divalent metal ions. ,,− …”