Titanium-Catalyzed Cycloisomerization of 1,6-Dienes. Regio- and Stereoselective Synthesis of e xo -Methylenecycloalkanes
2000; American Chemical Society; Volume: 19; Issue: 8 Linguagem: Inglês
10.1021/om991024l
ISSN1520-6041
AutoresSentaro Okamoto, Tom Livinghouse,
Tópico(s)Synthetic Organic Chemistry Methods
ResumoCycloisomerization of 1,6-dienes 1 in the presence of a catalytic amount of n-BuMgBr and a variety of organotitanium complexes such as Cp2TiCl2, Cp(MeO)TiCl2, Cp(Me2N)TiCl2, or CpTi[(TMS)2NC(NCy)2)Cl2 provided the corresponding 2-methyl-1-methylenecyclopentanes 2 with high efficiency. In contrast, catalysis using the more sterically encumbered complex ethylenebis(tetrahydroindenyl)titanium dichloride led to the predominant formation of methylenecyclohexanes 3.
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