π-Allylic C1-Substitution in Water with Nitromethane Using Amphiphilic Resin-Supported Palladium Complexes
作者:Yasuhiro Uozumi、Toshimasa Suzuka
DOI:10.1021/jo061250m
日期:2006.10.1
palladium-catalyzed π-allylic substitution in water with amphiphilic PS−PEG resin-supported phosphine−palladium complexes. Catalyticasymmetric nitromethylation of cycloalkenyl esters was achieved in water as a single reaction medium under heterogeneous conditions using 5 mol % palladium of a PS-PEG resin-supported palladium−imidazoindolephosphine complex to give optically active (cycloalkenyl)nitromethanes
(R)-cyclopent-2-enecarboxylic acid (15) in excellent yield and high enantiomeric purity (>98% ee). 6-exo-trig atom-transfer radicalcyclizations of ((R)-cyclopent-2-enyl)methyl 2-iodoacetate (12) produced exclusively the desired cis-fused δ-lactone (4aR,7aR)-hexahydro-5-iodocyclopenta[c]pyran-3(1H)-one (11), which was subsequently elaborated to hydroxylactone 1 through a stereocontrolled Pd(II)-mediated