Palladium-catalyzed [4 + 2] cycloaddition of o-(silylmethyl)benzyl esters with ketones: an equivalent to oxo-Diels-Alder reaction of o-xylylenes.
o-(Silylmethyl)benzyl carbonates reacted with various electron-deficient ketones in the presence of a palladium catalyst, affording the [4 + 2] cycloaddition products, isochromanes, in high yields. The palladium-catalyzed cycloaddition is equivalent to the oxo-Diels-Alder reaction of o-xylylene with ketones. The regioselectivities were extraordinarily affected by the structures of the o-xylylene precursors and ketones. The unusual regiochemistry may support two competitive reaction pathways in the catalytic reaction.
Ueno
Satoshi
S
Department of Chemistry, Graduate School of Sciences, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, Japan.
Ohtsubo
Masakazu
M
Kuwano
Ryoichi
R
D001554:Benzene / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D004952:Esters / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry*; D008745:Methylation; D015394:Molecular Structure; D010165:Palladium / Q000737:chemistry*; D013237:Stereoisomerism; D014992:Xylenes / Q000737:chemistry*
D004952:Esters; D007659:Ketones; D014992:Xylenes; D010165:Palladium; D001554:Benzene