Chelation control through the coordination of an olefinic π-bond to Lewis acid

The reaction of a 1:1 mixture of ortho-alkenylbenzaldehydes 3 and their para-isomers 4 with Bu 3SnH (1 equiv.) in the presence of Me 3Al (1 equiv.) resulted in very high (>10:1) to good (3.4:1) chemoselective reduction of 3, giving the ortho-alkenyl benzyl alcohol 5 selectively. Similarly, the hi...

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Bibliographic Details
Published inTetrahedron letters Vol. 41; no. 49; pp. 9533 - 9536
Main Authors Asao, Naoki, Shimada, Tomohiro, Yamamoto, Yoshinori
Format Journal Article
LanguageEnglish
Published OXFORD Elsevier Ltd 02.12.2000
Elsevier
Subjects
alkenes
allylation
carbonyl compounds
chelation
Chemistry
Chemistry, Organic
Lewis acid
Physical Sciences
reduction
Science & Technology
Lewis acid
alkenes
reduction
carbonyl compounds
allylation
chelation
ALUMINUM
ADDITION-REACTIONS
ALPHA
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Summary:The reaction of a 1:1 mixture of ortho-alkenylbenzaldehydes 3 and their para-isomers 4 with Bu 3SnH (1 equiv.) in the presence of Me 3Al (1 equiv.) resulted in very high (>10:1) to good (3.4:1) chemoselective reduction of 3, giving the ortho-alkenyl benzyl alcohol 5 selectively. Similarly, the highly chemoselective allylation of 3d in the presence of 4d was observed when the mixture was treated with allyltributyltin/Me 3Al. The chemoselectivities are most probably due to the bidentate chelation of the Lewis acid to an olefinic π-bond and a lone pair of aldehydes.
ISSN:0040-4039
1873-3581
DOI:10.1016/S0040-4039(00)01667-1