Boranes in Synthesis. 6. A New Synthesis of β-Amino Alcohols from Epoxides. Use of Lithium Amides and Aminoborane Catalysts To Synthesize β-Amino Alcohols from Terminal and Internal Epoxides in High Yield

Article abstract of DOI:10.1021/jo00104a034

A study of the conversion of terminal and internal epoxides to the corresponding β-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 deg C to give a single regioisomer of the corresponding β-amino alcohols in 80-100percent 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 catalists, 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 deg C in diethyl ether in the presence of a catalytic amount of B-bromo-9-BBN afforded the corresponding β-amino alcohols in 70-95percent isolated yield.