Synthesis, Resolution, and Application of Cyclobutyl- and Adamantyl-Quinazolinap Ligands

An expedient, seven-step synthesis of two new members of the Quinazolinap, hgand family, 2-cyclobutyl- and 2-(1-adamantyl)-Quinazohnaps, has been developed. The racemic ligands have been efficiently resolved by fractional crystallization of their diastereomeric palladacycle complexes. The enantioenriched ligands provide good levels of enantioselection (ee's up to 89%) in a prototypical Pd-II-catalyzed allylic alkylation reaction. 2-Cyclobutyl-Quinazohnap has been further functionalized at the 2-position via metalation with a superbase followed by reaction with a range of electrophiles. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)