Preparation and reactions of 3-oxa- and 4-oxa-5-hexenyllithiums
✍ Scribed by William F. Bailey; Eric R. Punzalan; Lyn M. J. Zarcone
- Book ID
- 102846510
- Publisher
- John Wiley and Sons
- Year
- 1992
- Tongue
- English
- Weight
- 701 KB
- Volume
- 3
- Category
- Article
- ISSN
- 1042-7163
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
Low‐temperature lithium–iodine exchange between tert‐butyllithium and the appropriate iodide has been used to generate 3‐oxa‐5‐hexenyllithium and a variety of 4‐oxa‐5‐hexenyllithiums. The 3‐oxa system is inherently unstable and fragments via facile β‐elimination to give the anion of allyl alcohol and ethylene. The 4‐oxa‐5‐hexenyllithiums, in contrast, are stable at low temperatures but undergo novel isomerization upon warming to deliver the lithium salt of a 4‐alken‐1‐ol in the formal equivalent of an unprecedented [1,4]‐Wittig rearrangement. The rearrangement is most likely mediated by 5‐exo‐trig ring closure of the 4‐oxa‐5‐hexenyllithium to a (2‐tetrahydrofuranyl)methyllithium followed by rapid opening to the alkoxide.
📜 SIMILAR VOLUMES
## Abstract Ring‐opening polymerization of the bicyclic lactone mixture **2**, __cis__/__trans__‐3‐oxa‐4‐oxo‐ and __cis__/__trans__‐4‐oxa‐3‐oxobicyclo[5.4.0]undecane with Sn(Oct)~2~ as a catalyst was investigated for the first time (Scheme 1). The lactones were obtained by Baeyer–Villiger oxidation
Single-crystal X-ray study T = 298 K Mean '(C±C) = 0.003 A Ê R factor = 0.047 wR factor = 0.144 Data-to-parameter ratio = 15.0 For details of how these key indicators were automatically derived from the article, see http://journals.iucr.org/e.