Ghosh Subhash, Kumar Soma Uday, Shashidhar J
Indian Institute of Chemical Technology, Hyderabad 500 007, India.
J Org Chem. 2008 Feb 15;73(4):1582-5. doi: 10.1021/jo7023152. Epub 2008 Jan 18.
A highly convergent total synthesis of bitungolide F leading to the assignment of its absolute stereochemistry is described. The key steps include a Horner-Wadsworth-Emmons olefination to construct the C7-C8 bond, a Wittig reaction to introduce the conjugate E,E-olefinic moiety in the molecule, and finally a ring-closing metathesis reaction to construct the six-membered alpha,beta-unsaturated delta-lactone of the molecule. Modified Evans's syn-aldol reaction, using Crimmins's protocol, was used to install the stereochemistries at the C4 and C5 centers. The stereochemistry at C9 was introduced by means of hydroxy-directed reduction of the C9 keto using Evans's protocol.
描述了一种高度汇聚的比通内酯F的全合成方法，并确定了其绝对立体化学结构。关键步骤包括通过霍纳-沃兹沃思-埃蒙斯烯化反应构建C7-C8键，通过维蒂希反应引入分子中的共轭E,E-烯烃部分，最后通过关环复分解反应构建分子中的六元α,β-不饱和δ-内酯。采用克里明斯方法对埃文斯的顺式羟醛反应进行改进，用于在C4和C5中心安装立体化学结构。通过使用埃文斯方法对C9酮进行羟基定向还原引入C9处的立体化学结构。
