Hot water as a mild Brønsted acid catalyst in ring opening reactions of epoxides
作者:ZhaoBing Xu、Jin Qu
DOI:10.1007/s11426-011-4323-x
日期:2011.11
Ring opening of extremely hydrophobic epoxides with water, amines, sodium azide and thiophenol was realized in the mixture solvent of water and 1, 4-dioxane under reflux condition. Hot water was believed to act as a mild Brønsted acid catalyst in the epoxide-opening reactions.
Boranes in Synthesis. 6. A New Synthesis of .beta.-Amino Alcohols from Epoxides. Use of Lithium Amides and Aminoborane Catalysts To Synthesize .beta.-Amino Alcohols from Terminal and Internal Epoxides in High Yield
作者:Clifford E. Harris、Gary B. Fisher、David Beardsley、Lawrence Lee、Christian T. Goralski、Lawrence W. Nicholson、Bakthan Singaram
DOI:10.1021/jo00104a034
日期:1994.12
A study of the conversion of terminal and internal epoxides to the corresponding beta-amino alcohols using simple primary and secondary lithium amides has been carried out. Thus, styrene oxide and 1,2-epoxydodecane react directly with primary and secondary lithium amides in THF at 25 degrees C to give a single regioisomer of the corresponding beta-amino alcohols in 80-100% isolated yields. Since internal epoxides are known to yield predominantly allylic alcohols when reacted with lithium amides, we employed a series of aminoborane Lewis-acid catalysts, generated in situ, to suppress formation of the allylic alcohols. Thus, the reaction of cyclohexene oxide with a variety of primary and secondary lithium amides at 34 degrees C in diethyl ether in the presence of a catalytic amount of B-bromo-9-BBN afforded the corresponding beta-amino alcohols in 70-95% isolated yield.