Vinodkumar Ramavath, Nakate Ashwini K, Gamidi Rama Krishna, Kontham Ravindar
Organic Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India.
Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
Org Lett. 2024 Aug 30;26(34):7116-7121. doi: 10.1021/acs.orglett.4c02357. Epub 2024 Aug 20.
In this study, we unveil the versatility of 4-pentyn-1-ols as carbonyl surrogates for the unprecedented synthesis of diverse oxygen heterocycles, including [5,6,5]-bis-spiroketals (trioxadispiroketals) and [5,6,5]-furano-spiroketals related to bioactive natural products. These reactions commence with the π-activation-induced intramolecular hydroalkoxylation of 4-pentyn-1-ols, yielding cyclic enol ethers, which undergo subsequent three-component annulation with aldehydes in a [2+2+1+1] fashion, resulting in the formation of [5,6,5]-bis-spiroketals. Notably, the distinctive steric features of alkynyl alcohols, particularly those with a secondary or tertiary alcohol functionality, dictate divergent reaction pathways, leading to the formation of [5,6,5]-furano-spiroketals.
在本研究中，我们揭示了4-戊炔-1-醇作为羰基替代物的多功能性，用于前所未有的多种含氧杂环的合成，包括与生物活性天然产物相关的[5,6,5]-双螺缩酮（三氧杂二螺缩酮）和[5,6,5]-呋喃螺缩酮。这些反应始于4-戊炔-1-醇的π-活化诱导的分子内氢烷氧基化，生成环状烯醇醚，其随后与醛以[2+2+1+1]方式进行三组分环化反应，从而形成[5,6,5]-双螺缩酮。值得注意的是，炔醇独特的空间特征，特别是那些具有仲醇或叔醇官能团的炔醇，决定了不同的反应途径，导致[5,6,5]-呋喃螺缩酮的形成。
