Practical Preparation of (4R,5R,E)-methyl 5-(tert-butyldimethylsilyloxy)-4-hydroxyhepta-2,6-dienoate

Abstract

This study is aimed to improve the preparation of uselful synthetic block (4R,5R,E)-methyl 5-(tert-butyldimethylsilyloxy)-4-hydroxyhepta-2,6-dienoate (1). This intermediate was used in the synthesis of (+)-Cladospolide D. The strategy developed by Voigtritter et al. was adopted to exploit the acceleration effect of copper (I) iodide. This compound was prepared from D-mannitol-derived dienediol (2) coupled with methyl acrylate through olefin cross-metathesis reaction in various conditions. It was found that performing the reaction in the presence of 3 mol% of CuI in refluxing diethyl ether gave the product up to 75% of yield with lower catalyst loading, i.e.: 2 mol%.

Structure Modification of Quinine on C-9 Hydroxyl Group via Esterification Reaction

“…H9 attached in carbon-beta of the ester, has position in the same side to H6, but has no signal interaction to H8. It reveals that H9 is the different side to H8 [26][27]. And also, interaction of H9 to H5' from aromatic ring as indication the twisted bicyclic ring of quinine (Figure 4).…”

Cyclopropanation of Various Substrates via Simmons-Smith and Michael-Initiated Ring Closure (MIRC) Reactions

“…Cinnamyl alcohol 18 was simply provided by reduction of cinnamaldehyde using sodium borohydride. Compound 25 was prepared in our previous work by metathesis reaction between commercially available methyl acrylate and TBS-protected C 2 symmetrical dine-diol which was derived from D-mannitol [19,20,21,22,25]. The subsequent protection as methoxymethyl ether gave compound 26 [23].…”