Suzuki Cross-Coupling on Enantiomerically Pure Epoxides: Efficient Synthesis of Diverse, Modular Amino Alcohols from Single Enantiopure Precursors
作者:Xavier Cattoën、Miquel A. Pericàs
DOI:10.1021/jo062612t
日期:2007.4.1
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), Pd-2(dba)(3)center dot 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 C-2 symmetrical bisoxazolines.