Stereoselectivity in Trimethylenemethane (TMM) Diyl Mediated Cycloaddition Reaction to Angularly Fused Triquinanes

A thorough study on the diastereoselectivity in the TMM diyl mediated [2+3] cycloaddition reaction of monosubstituted linear substrates to form angularly fused triquinanes was carried out. Substitution at position 3 provided complete diastereoselectivity, while positions 1 and 4 induced marginal stereoselectivity. Position 2 did not show any influence on the diastereoselectivity. Position 4 turned out to be incompatible with the cycloaddition reaction as the carbene intermediate underwent OSi bond insertion to form a dihydrofuran ring.