𝔖 Bobbio Scriptorium
✦   LIBER   ✦

First [2+2]-cycloaddition of a 3,4-didehydropyridine and a ketene dialkyl acetal

✍ Scribed by Natacha Mariet; Malika Ibrahim-Ouali; Maurice Santelli

Publisher
Elsevier Science
Year
2002
Tongue
French
Weight
62 KB
Volume
43
Category
Article
ISSN
0040-4039

No coin nor oath required. For personal study only.

✦ Synopsis

The 3-or 4-halopyridines and a ketene dialkyl acetal were shown to permit the synthesis of pyrido[b]cyclobutene derivatives. This finding constitutes the first published report of cycloadditions involving an olefin and a 3,4-pyridyne partner. The reaction is totally regioselective and the structure of the cycloadduct is determined unambiguously by NMR experiments.

πŸ“œ SIMILAR VOLUMES

ZnCl2-catalysed cycloadditions between k
ZnCl2-catalysed cycloadditions between ketene acetals and Ξ±,Ξ²-unsaturated carbonyl compounds. A simple route to 2,2-dialkoxy-3,4-dihydropyrans
✍ C. G. Bakker; J. W. Scheeren; R. J. F. Nivard πŸ“‚ Article πŸ“… 2010 πŸ› Elsevier Science 🌐 English βš– 665 KB

## Abstract 2,2‐Dialkoxy‐3,4‐dihydropyrans (3) can be obtained under mild conditions and in good yields from ketene acetals (1) and Ξ±,β‐unsaturated carbonyl compounds (**2**) in the presence of ZnCl~2~. At low temperatures (< βˆ’20Β°C) the reaction between **1** and **2** proceeds as a (2 + 2)‐cycload