136379-69-6Relevant academic research and scientific papers
Intramolecular Alkoxide Induced Heterolysis of Perhydronaphthalene-1,4-diol Monosulfonate Esters through Orbital Interactions over Three C-C Single Bonds
Orru, Romano V. A.,Wijnberg, Joannes B. P. A.,Jenniskens, Louis H. D.,Groot, Aede de
, p. 1199 - 1206 (2007/10/02)
The course of the reactions that occur when stereochemically rigid trans-perhydronaphthalene-1,4-diol monosulfonate esters (1-4) are treated with alkali metal tert-amylate in refluxing benzene depends on the relative orientation of the leaving group and the tertiary hydroxyl group.An equatorial sulfonate ester group homofragmentation leading to the cyclopropane derivative 15.In case of an axial sulfonate ester group β-elimination, which strongly depends on the stereochemistry of the tertiary deprotonated hydroxyl group, is the main reaction path.The O-silylated mesylates 5 and 6 show no reaction at all upon treatment with strong base; fast reactions are observed when 5 and 6 are treated with TBAF.Generation of an alcoholate is crucial for the observed reactions.Homofragmentation and an internal return reaction with inversion of configuration of the mesylate group in the axial mesylates 1 and 3 is explained by assuming a stabilized 1,3-bridged intermediate carbocation.This also explains why the equatorial mesylates react slightly faster than the axial mesylates.The reactivity of the α-mesylates is controlled by through-bond induction alone, whereas the reactivity of the corresponding β-mesylates is determined by the sum of a through-bond and a through-space (1,3-bridging) interaction.
Base-Induced and -Directed Elimination and Rearrangement of Perhydronaphthalene-1,4-diol Monosulfonate Esters. Total Synthesis of (+/-)-Alloaromadendrane-4β,10α-diol and (+/-)-Alloaromadendrane-4α,10α-diol
Jenniskens, Louis H. D.,Wijnberg, Joannes B. P. A.,Groot, Aede de
, p. 6585 - 6591 (2007/10/02)
The total synthesis of (+/-)-alloaromadendrane-4β,10α-diol (1), supposedly isolated from Ambrosia peruviana Willd., is described.The strategically positioned axial hydroxyl group at C(4) played a crucial role in the two key steps of this synthesis (2 and 11 -> 3; 4 -> 5).Upon treatment with sodium tert-amylate in refluxing toluene, both the mesylates 2 and 11 predominantly gave the olefin 3.A mechanism for this regioselective elimination is proposed.The double bond of 3 at C(6)-C(7) was used to introduce a dimethylcyclopropane ring at this position.The intramolecular base-induced rearrangement of 4 proceeded with high selectivity, again guided by the alkoxide at C(4).The resulting exo olefin 5 was converted into diol 1, but its spectral data did not agree with those reported for the natural diol.The epimeric (+/-)-alloaromadendrane-4α,10α-diol (23) was prepared from 5 via a dehydratation, epoxidation, reduction sequence.Now the spectral data of the natural and the synthetic diol agreed very well and a revision of the structure of the natural product is postulated.
