Novel route to fused nitrogen heterocycles by olefin metathesis
作者:Stephen F. Martin、Yusheng Liao、Hui-Ju Chen、Michael Pätzel、Melissa N. Ramser
DOI:10.1016/0040-4039(94)88060-3
日期:1994.8
A novel technique for the efficient synthesis of fused nitrogen heterocycles has been developed that features the molybdenum alkylidene-catalyzed metathesis of α,ω-dienes containing a nitrogen atom in the chain linking the two olefinic functional groups. The starting materials may be readily prepared in three steps from succinimide and glutarimide via sequential Mitsunobu alkylation, sodium borohydride
The cyclization of α-N-acyliminium ions generated from ethoxylactams 1–3 using trifluoroacetic acid, trifluoromethanesulfonic acid and anhydrous HF affords ketones, bromoalkenes and geminal bromofluoro compounds, respectively. A non concerted process explains these results which demonstrate the high reactivity of the intermediate bromocarbenium ions with different nucleophiles. The unexpected fluorination