Oxidation Under Reductive Conditions: From Benzylic Ethers to Acetals with Perfect Atom‐Economy by Titanocene(III) Catalysis
作者:Pierre Funk、Ruben B. Richrath、Fabian Bohle、Stefan Grimme、Andreas Gansäuer
DOI:10.1002/anie.202013561
日期:2021.3
oxygen rebound as a reductive elimination. The reaction mechanism was studied by high‐level dispersion corrected hybrid functional DFT with implicit solvation. The low‐energy conformational space was searched by the efficient CREST program. The stereoselectivity was deduced from the lowest lying benzylic radical structures and their conformations are controlled by hyperconjugative interactions and steric
Total synthesis of milbemycins: a synthesis of (6R)-6-hydroxy-3,4-dihydromilbemycin E
作者:Madeleine Helliwell、Sufia Karim、Emma R. Parmee、Eric J. Thomas
DOI:10.1039/b508670a
日期:——
of the corresponding (9Z,2'E)-isomers 60 and 61. (2'Z)/(2'E)-Isomerisation of the dienes 58 and 59 using iodine followed by deprotection gave a mixture of the seco-acids 62 and 63. Selective macrocyclisation of the seco-acid 62 in which the relative configuration of the C1-C7 and C17-C19 fragments (milbemycin numbering) corresponded to that present in the natural milbemycins, gave the beta-milbemycin