Addition of lithium bis(methylenecyclopropyl)cuprates to acetoxy azetidinones gives methylenecyclopropyl azetidinones, which can be converted to various radical cyclisation precursors. Attempted 4-exo cyclisation of 3 led only to reduced product, while cyclisation of 5, using CuCl/bipy, gave a carba
Cascade radical cyclisations of methylenecyclopropyl ketones—synthesis of bicyclo-[3.2.1]-octanes
✍ Scribed by Alexandre C. Saint-Dizier; Jeremy D. Kilburn
- Publisher
- Elsevier Science
- Year
- 2002
- Tongue
- French
- Weight
- 226 KB
- Volume
- 43
- Category
- Article
- ISSN
- 0040-4039
No coin nor oath required. For personal study only.
✦ Synopsis
Samarium diiodide mediated cyclisation of methylenecyclopropyl ketones, readily prepared from b-ketoesters provides a simple route to bicyclo-[3.2.1]-octanes.
📜 SIMILAR VOLUMES
## Abstract Starting from the easily accesible chiral aldehyde 2, we obtained enantiomerically pure (__Z__)‐ and (__E__)‐α,‐chloro‐α,β‐unsaturated esters 4c in good yields by olefination reactions. (__Z__)‐and (__E__)‐4c were allowed to react with the kinetically controlled generated lithium dienol
The 8-chlorobicyclo[3.2.1]oct-6-ene 3 has been prepared by a [3+2] cycloaddition route, and converted to the bicyclic a-methylene ketones 6 and 8-12, some of which showed cytotoxic properties.
The 'H and I3C NMR spectra of six bromo-and methoxybicyclo[3.2.1]octanes were completely assigned. An axial bromine substituent at C-2 or C-4 results in a 5 ppm upfield shift of C-8 due to the gauche interaction. An equatorial bromine results in an upfield shift of similar magnitude on either C-6 (o
The bicyclo[3.2.l]octane ring system is assembled by a three-step process featuring a thermally induced [4+2] cycloaddition followed by a 1,3benzodithiolium ion mediated cyclization onto an enol or silyl enol ether double bond. The bicyclo[3.2.l]octane carbon skeleton is a common structural subunit