A one‐pot synthesis of 1′‐methyl‐2′‐oxospiro [indene‐1, 3′‐indoline] and 3,3‐disubstituted 2‐oxindole derivatives in excellent combined yield by the reaction of methoxy isomerized MBH adducts of isatin with arynes and heteroarynes has been achieved. A plausible mechanism invoking a [3+2]‐spiro‐ annulation reaction and quenching the intermediate with proton is explained. Formation of regioselective products from unsymmetrical arynes is explained based on reactivity profiles of arynes/heteroarynes. Synthetic utility of synthesized compounds have been demonstrated.

A BF3·Et2O mediated reaction of co-planar 9-(phenylethynyl)-9H-fluoren-9-ol with various isatin imines afforded title compounds in excellent yield. The products showed luminescence in the blue region with large Stokes shift.

Reaction of aryne with isatin based N,N′-cyclic AMI 1,3-dipole afforded 3,3-disubstituted oxindole while methyl substitution on the pyrrolidine ring of 1,3-dipole directed [3+2] cycloaddition products.

A boron trifluoride catalysed reaction of coplanar 9-(phenyl­ethynyl)-9H-fluoren-9-ols with various 2-aminobenzamides affords a number of highly functionalized, conjugated (Z)-2-((2-(9H-fluoren-9-ylidene)-1-phenylethylidene)amino) benzamides in excellent yield. The reaction in the presence of N-bromosuccinimide affords (E)-5-bromo-2-((2-bromo-2-(9H-fluoren-9-ylidene)-1-phenylethylidene)amino)benz­amides in very good yields. The scope of the reaction is demonstrated by selecting N-aryl substituted 2-aminobenzamides and aminosulfonamides as reaction partners. The structures of representative compounds were established by single-crystal XRD analysis. Based on the structure of the products, a plausible mechanism via formation of allene carbocation intermediates is proposed.