Insect pheromone synthesis using Mn-salen catalyzed asymmetric epoxidation as a key step

Alkyne‐Mediated Approach for Total Syntheses of Cladospolides A, B, C and iso‐Cladospolide B

“…For the approach towards cladospolide A (see Scheme ), we began by synthesizing alkynol 7 from epoxide 6 through a two‐step sequence7a,11 that involved: (i) an epoxide ring‐opening reaction with 1‐hexyne and n BuLi/hexamethylphosphoramide (HMPA) and (ii) a KH‐mediated alkyne‐zipper reaction 12. The spectroscopic data of alkynol 7 was in agreement with the reported data, and the specific rotation was comparable with the literature value 13. Furthermore, the optical purity was measured at the next stage, that is, after protection of the secondary alcohol as the tert ‐butyldiphenylsilyl (TBDPS) ether 8 , which was carried out in 82 % yield 14.…”

Development of an efficient magnetically separable nanocatalyst: theoretical approach on the role of the ligand backbone on epoxidation capability

“…6,7 Besides, the chiral epoxides play an eminent role as drug intermediates and chiral building blocks in the synthesis of optically active complex molecules. [8][9][10][11] In the literature, transition metal Schiff base complexes have been extensively used as homogeneous catalysts for epoxidation. [12][13][14][15] They show high efficiency since the active site is easily accessible, but their separation from the reaction mixture is really a difficult task.…”

Isolation of (E)-9,10-dihydroxy-2-decenoic acid from royal jelly and determination of the absolute configuration by chemical synthesis

“…The stereochemistry at the C-9 position was estimated to be (R) by comparison of the sign of the specific rotation {½a 23 D ¼ þ6:3 (c 0.50, methanol)} of 1 with those of related compounds. 16,18,19 …”

“…15,16 The absolute stereochemistries of 4 and (E)-9-hydroxy-2-decenoic acid have been determined to be (3R) and (9R/9S) = 2:1, respectively, 15 by applying the modified Mosher's method, 17 whereas the absolute configurations of the other compounds have been determined to be (S) by comparison of the signs of the specific rotation with their analogues. 18,19 In the course of our studies searching for biological active compounds in royal jelly, we found 9,10-dihydroxy-2-decenoic acid 1 as a new compound. Described herein are the isolation, structural determination, and total synthesis of 1.…”