Inyutina Anna, Kantin Grigory, Dar In Dmitry, Krasavin Mikhail
Saint Petersburg State University, Saint Petersburg 199034, Russian Federation.
J Org Chem. 2021 Oct 1;86(19):13673-13683. doi: 10.1021/acs.joc.1c01710. Epub 2021 Sep 13.
We report on a facile method for the preparation of 2-benzoxepine derivatives as a result of Rh(II)-catalyzed decomposition of diazo arylidene succinimides in the presence of aldehydes. The process is thought to involve the formation of styryl carbonyl ylide which undergoes 1,7-electrocyclization and subsequent 1,5-hydrogen shift. In some cases, the competition of the target reaction and [3+2] dipolar cycloaddition of the intermediate carbonyl ylide to another molecule of diazo substrate was observed. Generally, the desired 2-benzoxepines were isolated in good to high yields and high diastereoselectivity. The developed original approach toward a 2-benzoxepine core via formal [5+2] cycloaddition of styryl carbenoids and aldehydes significantly expands the arsenal of synthetic methods for producing this scaffold.
我们报道了一种简便的方法，用于制备2-苯并氧杂环庚三烯衍生物，该方法是通过在醛存在下铑（II）催化的重氮亚苄基琥珀酰亚胺的分解来实现的。该过程被认为涉及苯乙烯基羰基叶立德的形成，其经历1,7-电环化和随后的1,5-氢迁移。在某些情况下，观察到目标反应与中间体羰基叶立德与另一分子重氮底物的[3+2]偶极环加成之间的竞争。通常，所需的2-苯并氧杂环庚三烯以良好至高的产率和高的非对映选择性被分离出来。通过苯乙烯基类卡宾和醛的形式[5+2]环加成来构建2-苯并氧杂环庚三烯核心的这种原创方法，显著扩展了用于制备该骨架的合成方法库。
