Oxygen and nitrogen heterocycles by intramolecular magnesium- and zinc-ene reactions; Methylenecyclopentanes by Pd(0) - catalyzed isomerization of 5-(bromozincmethyl)-3-methyleneoxacycloalkanes
作者:J. van der Louw、J.L. van der Baan、H. Stieltjes、F. Bickelhaupt、G.W. Klumpp
DOI:10.1016/s0040-4039(01)81093-5
日期:1987.1
2-(Alkenyloxymethyl)-2-propenylzinc bromides 2a-e and 2-(allylmethylaminomethyl)-2-propenylzinc (or magnesium) halides 2g rearrange thermally to 5-(l-bromozincalkyl)-3-methyleneoxacycloalkanes 1a-e and 5-(bromozinc[or chloromagnesium]methyl)-3-methylene-N-methylpiperidine 1g; some of the former can be isomerized by Pd(PPh3)4 to methylenecyclopentanes 3.
Practical preparation and metallo-ene reactions of (2-alkenylallyl)-magnesium chlorides: Comparative study of magnesium activation
作者:Wolfgang Oppolzer、Philippe Schneider
DOI:10.1016/s0040-4039(01)81370-8
日期:1984.1
Magnesium activated by equilibration with its anthracene adduct in THF metalates smoothly 2-alkenyl chlorides at −65°C without significant coupling. The resulting solutions of Grignard reagents are subjected to thermal (80–130°C) cyclization followed by trapping with electrophiles.