Organic Chemistry Division III, Indian Institute of Chemical Technology (CSIR), Hyderabad, India.
Org Biomol Chem. 2011 Jun 7;9(11):4079-84. doi: 10.1039/c1ob00019e. Epub 2011 Apr 15.
Radical cyclization reactions were performed by 5-exo-dig mode to yield cis-fused bicyclic systems, leading to the synthesis of bis-butyrolactone class of natural products. The study was aimed at understanding the impact of alkyl side chains of furanoside ring systems in L-ara configuration on the radical cyclization. It was amply demonstrated by experimental studies that the increase in the length of the alkyl side chain has an effect on the cyclization: while efficient cyclization reactions could be realized with methyl and ethyl side chains, the yields were significantly reduced in the case of n-pentyl side chain. Theoretical studies using DFT and (RO)MP2 methods were carried out to analyze the influence of the substitution pattern on the cyclization barriers.
自由基环化反应以 5-endo-方式进行，生成顺式稠合双环体系，从而合成双丁内酯类天然产物。本研究旨在了解 L-阿拉伯呋喃糖环系统中烷基侧链在 L-构型中的影响。实验研究充分证明，烷基侧链长度的增加对环化有影响：虽然甲基和乙基侧链可以实现高效的环化反应，但在正戊基侧链的情况下，产率显著降低。使用 DFT 和 (RO)MP2 方法进行的理论研究分析了取代模式对环化势垒的影响。
