Absolute Configuration for 1,<i>n</i>-Glycols: A Nonempirical Approach to Long-Range Stereochemical Determination
作者:Xiaoyong Li、Carmin E. Burrell、Richard J. Staples、Babak Borhan
DOI:10.1021/ja2119767
日期:2012.6.6
n-glycols (n = 2-12, 16) bearing two chiral centers were rapidly determined via exciton-coupled circulardichroism (ECCD) using a tris(pentafluorophenyl)porphyrin (TPFP porphyrin) tweezer system in a nonempirical fashion devoid of chemical derivatization. A unique "side-on" approach of the porphyrintweezer relative to the diol guest molecule is suggested as the mode of complexation.
The total synthesis of a novel antitumor cyclic depsipeptide FE399 was achieved mainly through the MNBA‐mediated macrolactamization. A combination of MNBA and a catalytic amount of DMAPO in the presence of triethylamine as coupling agents was found to be effective for the synthesis of the macrolactam core of FE399.
A firsttotal synthetic route has been reported for the synthesis of Phomolide G and H. The syntheses of fragments were initiated from commercially available and inexpensive starting material (R)-epichlorohydrin. The synthesis involves a key Sharpless epoxidation, stereoselective epoxide opening, lactonization and ring closing metathesis (RCM).
has been achieved. The key steps include the intramolecular SNAr reaction for construction of the densely functionalized xanthone skeleton, the stereoselective lactone cleavage using a chiral nucleophile to induce the axial stereochemistry, and the SmI2‐mediatedpinacol cyclization for the stereocontrolled conversion of axially chiral biaryl dialdehyde into the corresponding trans diol.
已经实现了对FD‐594六环核的立体控制访问。关键步骤包括:分子内S N Ar反应,用于构建密集功能化的蒽酮骨架;使用手性亲核试剂进行立体选择性内酯裂解,以诱导轴向立体化学;以及SmI 2介导的频哪醇环化,用于轴向控制性转化轴向手性联芳基二醛转化为相应的反式 二醇。