Olefin Metathesis Reactions of Some Aromatic Dienes with ortho- and meta- Disubstitution. Formation of 10-, 12-, 14-, and 17-Membered Cyclic Compounds and Isomerization of an Allylic Alcohol

Abstract

Some aromatic dienes with ortho-and meta-disubstitution have been subjected to olefin metathesis reactions.Compounds having allylphenyl groups substituted at their ortho positions successfully cyclized into 12-, 14-, and 17membered alkenes in moderate to good yields, while compounds having the same groups substituted at their meta positions and those having vinylphenyl groups substituted at their ortho positions afforded mainly polymers.o-Allylphenyl 5hexenyl ether produced 10-membered cyclooxadecadiene in 7.5% yield.2][3][4][5][6][7] Although considerable amounts of examples have been reported, it is not easy to find out the specific positions for favorable cyclization reactions to form medium and large rings. 8The different positions for cyclizations lead to different yields (sometimes disappointingly poor). 8[3][4][5][6][7] There are some examples to construct 10-membered rings, lactone (3) fused with a cyclopentanone (eq.2), 9 a part of marine polyether (4) (eq.3), 10 lactone (5) (eq.4), 11 oxasilacycle (6) (eq.5), 12 oxazacycle (7) (eq.6), 13 oxacycle (8) (eq.7), 14 and dioxacycle (9) (eq.8) 14 in 3-88% yield.We have encountered that diene (10) did not afford the desirable cyclodecene at all with catalyst (11). 15However, the diene (24) has successfully cyclized to a 10-membered cyclic ether (25) in spite of poor yield (7.5%).Thus, carbocycles seem to be more difficult to be formed by RCM reactions than heterocycles, presumably because of the absence of interaction between the catalyst and hetero atoms as discussed by Fürstner. 4,14nthesis of cyclic diarylheptanoids 16 such as 2, which has a hetero atom in its 15-membered ring, may be accomplished by the RCM reaction (eq. 1) of diene (1).Therefore, we have tested whether the orthoand meta-disubstituted dienes cyclize into medium and large rings by RCM reactions and found that compounds having allylphenyl groups substituted at their ortho positions successfully cyclized into 12-, 14-, and 17-membered alkenes in 52-79% yields, while compounds having the same groups substituted at their meta positions and those having vinylphenyl groups substituted at their ortho positions afforded mainly polymers.We now report the details of these successful and unsuccessful reactions.