Bc. Hong et al., METAL-MEDIATED [6-CYCLOADDITION REACTIONS OF FULVENES - A NOVEL-APPROACH TO INDAN SYSTEMS(3]), Journal of organic chemistry, 62(22), 1997, pp. 7717-7725
The [6 + 3] cycloaddition of 2-oxyallyl cations to the electron rich f
ulvene ketene acetal provides an efficient route to the indan skeleton
. The structures of these indan adducts were assigned by extensive 2D
NMR experiments. Direct hydrolysis of these ketal adducts affords the
corresponding diketones or indens. Reaction of the fulvene ketene thio
acetal as well as the tandem [6 + 3]-[4 + 3] cycloadditions were also
studied. A mechanism is proposed which may account for the origin of s
tereo-and regioselectivity in this cycloaddition.