The unsymmetrical silaketal as a neutral, removable tether for effecting intramolecular diels-alder reactions.

✍ Scribed by John W. Gillard; Réjean Fortin; Erich L. Grimm; Michel Maillard; Michael Tjepkema; Michael A. Bernstein; Robert Glaser

• Publisher: Elsevier Science
• Year: 1991
• Tongue: French
• Weight: 283 KB
• Volume: 32
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)92029-x

✦ Synopsis

Silaketals, in which reactive dienes and dienophiles are linked, can participate in intramolecular Diels-Alder reactions to produce products with a high degree of stereocontrol and with regiochemistry opposite to that predicted by bond polarization models.

Intmmolecular reaction processes which result from linking the reactive species frequently lead to higher expression of regio and stereochemical preferences'. The subsequent removal of the linking species may produce compounds in which bond formation has been achieved with enhanced regio-and stereochemical control. However, tethers which impose intramolecularity frequently interfere with the bond forming process. In Die&Alder chemistry, removable tethers such an ester?. ether?, amides4, ureas5, and carbamatess, have been examined and shown to have variable impact in controlling