Rearrangement vs Homofragmentation: Chemical Consequences of Different .sigma.-Relays on the Heterolysis of Sulfonate Esters Induced by Through-Bond Interactions
摘要:
An alcoholate function intramolecularly induces heterolysis of a sulfonate ester group in an apolar solvent via orbital interactions through three intervening C-C single bonds (TBI). It is shown that the reactivity of rigid trans-perhydronaphthalene-1,4-diol monosulfonate esters (1-6) upon treatment with sodium tert-amylate in refluxing benzene is only affected by the relative position of the hydroxyl function to the sulfonate ester group and not by the orientation of the hydroxyl group. The two chief pathways by which these compounds react are rearrangement (1, 3, and 4) and homofragmentation (5 and 6). Stereoelectronic effects play a dominant role here, except in compound 2 where steric factors primarily determine the reactivity and product outcome (ether formation). Homofragmentation is much faster than rearrangement and is only possible when a 1,3-bridged through-space interaction accompanies TBI. The extent of TBI as well as the product composition is strongly determined by the sigma-relay of the three C-C bonds between the electron donor (alcoholate) and the electron acceptor (sulfonate ester bond). The results presented here are consistent with the trans rule and show the validity of similar proposals for biosynthetic processes.
Rearrangement vs Homofragmentation: Chemical Consequences of Different .sigma.-Relays on the Heterolysis of Sulfonate Esters Induced by Through-Bond Interactions
摘要:
An alcoholate function intramolecularly induces heterolysis of a sulfonate ester group in an apolar solvent via orbital interactions through three intervening C-C single bonds (TBI). It is shown that the reactivity of rigid trans-perhydronaphthalene-1,4-diol monosulfonate esters (1-6) upon treatment with sodium tert-amylate in refluxing benzene is only affected by the relative position of the hydroxyl function to the sulfonate ester group and not by the orientation of the hydroxyl group. The two chief pathways by which these compounds react are rearrangement (1, 3, and 4) and homofragmentation (5 and 6). Stereoelectronic effects play a dominant role here, except in compound 2 where steric factors primarily determine the reactivity and product outcome (ether formation). Homofragmentation is much faster than rearrangement and is only possible when a 1,3-bridged through-space interaction accompanies TBI. The extent of TBI as well as the product composition is strongly determined by the sigma-relay of the three C-C bonds between the electron donor (alcoholate) and the electron acceptor (sulfonate ester bond). The results presented here are consistent with the trans rule and show the validity of similar proposals for biosynthetic processes.
Rearrangement vs Homofragmentation: Chemical Consequences of Different .sigma.-Relays on the Heterolysis of Sulfonate Esters Induced by Through-Bond Interactions
作者:Romano V. A. Orru、Joannes B. P. A. Wijnberg、Catharina T. Bouwman、Aede de Groot
DOI:10.1021/jo00081a016
日期:1994.1
An alcoholate function intramolecularly induces heterolysis of a sulfonate ester group in an apolar solvent via orbital interactions through three intervening C-C single bonds (TBI). It is shown that the reactivity of rigid trans-perhydronaphthalene-1,4-diol monosulfonate esters (1-6) upon treatment with sodium tert-amylate in refluxing benzene is only affected by the relative position of the hydroxyl function to the sulfonate ester group and not by the orientation of the hydroxyl group. The two chief pathways by which these compounds react are rearrangement (1, 3, and 4) and homofragmentation (5 and 6). Stereoelectronic effects play a dominant role here, except in compound 2 where steric factors primarily determine the reactivity and product outcome (ether formation). Homofragmentation is much faster than rearrangement and is only possible when a 1,3-bridged through-space interaction accompanies TBI. The extent of TBI as well as the product composition is strongly determined by the sigma-relay of the three C-C bonds between the electron donor (alcoholate) and the electron acceptor (sulfonate ester bond). The results presented here are consistent with the trans rule and show the validity of similar proposals for biosynthetic processes.