Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI 1000 Ljubljana, Slovenia.
Department of Chemistry, College of Science, Sultan Qaboos University, P.O. Box 36, Al Khoud Muscat, Oman.
Molecules. 2017 Dec 21;23(1):3. doi: 10.3390/molecules23010003.
Asymmetric [3+2] cycloadditions of azomethine imines comprise a useful synthetic tool for the construction of pyrazole derivatives with a variable degree of saturation and up to three stereogenic centers. As analogues of pyrrolidines and imidazolidines that are abundant among natural products, pyrazoline and pyrazolidine derivatives represent attractive synthetic targets due to their extensive applications in the chemical and medicinal industries. Following the increased understanding of the mechanistic aspect of metal-catalyzed and organocatalyzed [3+2] cycloadditions of 1,3-dipoles gained over recent years, significant strides have been taken to design and develop new protocols that proceed efficiently under mild synthetic conditions and duly benefit from superior functional group tolerance and selectivity. In this review, we represent the current state of the art in this field and detailed methods for the synthesis of non-racemic pyrazolines and pyrazolidines via [3+2] metal and organocatalyzed transformations reported since the seminal work of Kobayashi et al. and Fu et al. in 2002 and 2003 up to the end of year 2017.
不对称[3+2]环加成反应的亚甲胺叶立德是构建吡唑衍生物的有效合成工具，这些吡唑衍生物具有不同程度的饱和度和多达三个立体中心。作为天然产物中丰富的吡咯烷和咪唑烷的类似物，吡唑啉和吡唑烷衍生物由于其在化学和医药工业中的广泛应用而成为有吸引力的合成目标。近年来，随着对金属催化和有机催化 1,3-偶极子[3+2]环加成反应的机理方面的理解不断加深，人们在设计和开发新的反应条件方面取得了显著进展，这些反应条件温和、合成条件高效，并具有优越的官能团耐受性和选择性。在这篇综述中，我们代表了该领域的最新进展，详细介绍了自 Kobayashi 等人和 Fu 等人在 2002 年和 2003 年的开创性工作以来，通过[3+2]金属和有机催化转化合成非外消旋吡唑啉和吡唑烷的方法。
