✦ LIBER ✦

The importance of vinylsilane stereochemistry and σ - π stabilization in iminium ion-vinylsilane cyclizations. A short total synthesis of the amaryllidaceae alkaloid (−) −epielwesine.

✍ Scribed by Larry E. Overman; Robert M. Burk

Publisher: Elsevier Science
Year: 1984
Tongue: French
Weight: 210 KB
Volume: 25
Category: Article
ISSN: 0040-4039
DOI: 10.1016/s0040-4039(01)81674-9

No coin nor oath required. For personal study only.

✦ Synopsis

cis-3a-Aryl-2,3,3a,4,5,7a-hexahydro-lH-indoles 5 and 10 are formed in excellenTyield from acid promoted cyclization of (Z)-Tinylsizne imines 2 and 9.

The failure of the corresponding (E)-vinylsilane isomer 4 to cyclize under similar conditions demonstrates that the B-silylcation l'ntermediates formed in these reactions derive significant stabilization from (T-T delocalization.

We recently reported that a variety of unsaturated azacyclics can be prepared by the intramolecular reaction of iminium ions with vinylsilanes.1 An

📜 SIMILAR VOLUMES

The cyanomethyl group for nitrogen prote

The cyanomethyl group for nitrogen protection and iminium ion generation in ring-enlarging pyrrolidine annulations. A short synthesis of the amaryllidaceae alkaloid d,1-crinine

✍ Larry E Overman; E.Jon Jacobsen 📂 Article 📅 1982 🏛 Elsevier Science 🌐 French ⚖ 199 KB

The preparation of cis-3a-aryl-4-oxo-decahydrocyclohepta[b]pyrroles and cis-3a-aryl-4-oxo-octahydroindoles is facilitated by using a cyanomethyl group to both protect nitrogen and serve as a precursor for a formaldehyde imlnlum ion. Recent publications from our laboratory have described the efficie