Suzuki cross-coupling on enantiomerically pure epoxides: efficient synthesis of diverse, modular amino alcohols from single enantiopure precursors.
Suzuki arylation of enantiopure (4-bromophenyl)- or (3,5-dibromophenyl)glycidyl ethers has been achieved in toluene under Buchwald conditions [ArB(OH)2 (1.1 equiv), Cs2CO3 (2 equiv), Pd2(dba)3.C6H6 (1 mol %), S-Phos (4 mol %), toluene, 100 degrees C] allowing for the formation of modular arylglycidyl ethers not directly available in enantiopure form by epoxidation routes. These bulky ethers, when submitted to regioselective and stereospecific ring opening with ammonia [aq NH3, LiClO4 (1 equiv), THF, microwave irradiation (80 W), 125 degrees C] in a sealed tube, provide access to novel enantiopure beta-amino alcohols which, in turn, provide an easy access to structurally complex C2 symmetrical bisoxazolines.
Cattoën
Xavier
X
Institute of Chemical Research of Catalonia (ICIQ), Av. Països Catalans, 16 43007 Tarragona, Spain.
Pericàs
Miquel A
MA