Department of Chemistry and Biochemistry, Florida Atlantic University , Boca Raton, Florida 33431-0991, United States.
Org Lett. 2017 Jul 21;19(14):3695-3698. doi: 10.1021/acs.orglett.7b01401. Epub 2017 Jul 6.
A versatile approach to isoxazolines and pyrazolines by the cyclization of alkyne substrates using tetrabutylammonium fluoride (TBAF) is described. The reported diheteroatom cycles were produced under mild reaction conditions and with broad product scope. Evidence is also provided for a vinyl anion intermediate produced under unusually mild conditions, which was trapped in situ as part of a tandem cyclization/aldehyde addition sequence. Finally, a deprotection/functionalization method is described, leading to a substituted pyrazoline in good diastereoselectivity.
本文描述了一种使用四丁基氟化铵(TBAF)使炔烃底物环化来合成异恶唑啉和吡唑啉的通用方法。所报道的双杂原子环在温和的反应条件下以广泛的产物范围生成。还提供了在异常温和的条件下生成的乙烯基阴离子中间体的证据,该中间体作为串联环化/醛加成序列的一部分被原位捕获。最后,描述了一种脱保护/官能化方法,以良好的非对映选择性得到取代的吡唑啉。