Complex stereochemical course of the mitsunobu “inversion” of allylic alcohols
作者:Vittorio Farina
DOI:10.1016/s0040-4039(00)70640-x
日期:——
The Mitsunobu esterification reaction of dicyclopentadienols yields mixtures of inversion and retention products. Deuterium labeling demonstrates variable levels of allylic rearrangement.
Mechanism of Lithium Perchlorate/Diethyl Ether-Catalyzed Rearrangement of α- and β-<i>endo</i>- and -<i>exo</i>-Dicyclopentadienyl Vinyl Ethers: Use of Deuterium Labeling and a Chiral Probe
作者:Namasivayam Palani、Anju Chadha、Kalpattu K. Balasubramanian
DOI:10.1021/jo970715t
日期:1998.8.1
Lithium perchlorate/diethyl ether (LPDE) mediated rearrangement of alpha- and beta-endo-dicyclopentadienyl vinyl ethers 5 and 6 resulted in the formation df the aldehyde 8, indicating that the mechanism is nonconcerted and the recombination of the ion pair occurs at the dissociated stage and not the intimate ion-pair stage. Proof of this came from deuterium-labeling studies and the use of an optically pure starting material. Furthermore, that the ionic intermediate formed must be symmetrical resulting in enantiomeric aldehydes from both normal and allylic attack corresponding to products of formal 1,3 and 3,3 shifts was seen in the chiral analysis of the benzoate derivative of the aldehydes formed from the optically pure vinyl ether.