Kumar A Sanjeeva, Chauhan Sachin, Swamy K C Kumara
School of Chemistry, University of Hyderabad, Hyderabad 500046, Telangana, India.
Org Lett. 2021 Feb 5;23(3):1123-1129. doi: 10.1021/acs.orglett.1c00076. Epub 2021 Jan 22.
Spiro-annulation involving δ-acetoxy allenoate and alkyl benzoisothiazole dioxide (-sulfonyl ketimine) triggered by DABCO/MeCOH combination leads to an via chemo- and regiospecific [4 + 2]-carboannulation and a new group is introduced. In contrast, DMAP-catalyzed benzannulation using the same reactants affords unsymmetrical -teraryls via Mannich coupling, sequential proton transfers, and C-N bond cleavage. Here, δ-acetoxy allenoate serves as a 4C-synthon and the carboannulation is completely base dependent and mutually exclusive.
由DABCO/MeCOH组合引发的涉及δ-乙酰氧基丙二烯酸酯和烷基苯并异噻唑二氧化物（-磺酰基酮亚胺）的螺环化反应，通过化学和区域特异性的[4 + 2] -碳环化反应生成一个 ，并引入了一个新的 基团。相比之下，使用相同反应物的DMAP催化的苯环化反应通过曼尼希偶联、连续质子转移和C-N键裂解得到不对称的 -三芳基化合物。在这里，δ-乙酰氧基丙二烯酸酯作为一个4C合成子，碳环化反应完全依赖于碱且相互排斥。
