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Multicomponent ring-opening/Huisgen cycloaddition reactions combined with CO2 capture with a polyurea-encapsulated copper salt as a catalyst that in situ formed from simple CuCl and soluble polyurea during the reaction were carried out successfully for the synthesis of β-hydroxytriazoles under exceptionally mild conditions, in which the polyurea-encapsulated copper(i) chloride proved to be a robust and recyclable catalyst system with high yields as well as excellent chemoselectivity in this reaction. [ABSTRACT FROM AUTHOR]

All aspects of the title reaction, essentially the only entry into optically active 3-monosubstituted-1-bromoallenes up to now, have been probed systematically for the first time. The new results show that: (1) there is no need to purify CuBr or to exclude air or moisture, (2) addition of Cu(II) led to even higher enantiopurity, and (3) Et 2O is the best solvent. Much better selectivities were obtained under the new conditions. [ABSTRACT FROM AUTHOR]