Base-Promoted Cascade Reactions for the Synthesis of 3,3-Dialkylated Isoindolin-1-ones and 3‑Methyleneisoindolin-1-ones

Cascade reactions
of ortho-carbonyl-substituted
benzonitriles with ((chloromethyl)­sulfonyl)­benzenes as pronucleophiles
led to new isoindolin-1-ones with a tetrasubstituted C-3 position
or to (Z)-3-(sulfonyl-methylene)­isoindolin-1-ones.
The reactions start from readily available materials, are carried
out under mild conditions, and do not require metal catalysis. Promoted
only by the cheap and environmentally benign K2CO3 as the base, up to six elemental steps can be combined in a single
pot. Hence, a sequential one-pot cascade/β-elimination/alkylation
furnished useful intermediates for the synthesis of aristolactam natural
products. The observed selectivity and the mechanism were investigated
by DFT studies.