metalation–deprotonation step mediated by carbonate (or phosphate, C and D). The
six-membered palladacycle then undergoes reductive elimination (step E) to give
the product and regenerate the Pd
0 catalyst.
A related synthesis of 3,3
0 -cyclopropyl oxindoles was reported by Takemoto et al.
[32]. Carbamoyl chloride 47, containing a cyclopropyl ring at the ortho position,
undergoes a Pd-catalyzed cyclization onto the benzylic C–H bond of the cyclopropane to provide the corresponding spirooxindole 44 in 60% yield (Scheme 13).
Intramolecular competition reactions investigated the chemoselectivity of the
Scheme 12 Proposed reaction mechanism for the synthesis of 3,3
0 -cyclopropyl spirooxindoles
Scheme 13 Takemoto’s synthesis of spirooxindoles and order of reactivity experiments
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D. Sustac Roman and A.B. Charette
six-membered palladacycle then undergoes reductive elimination (step E) to give
the product and regenerate the Pd
0 catalyst.
A related synthesis of 3,3
0 -cyclopropyl oxindoles was reported by Takemoto et al.
[32]. Carbamoyl chloride 47, containing a cyclopropyl ring at the ortho position,
undergoes a Pd-catalyzed cyclization onto the benzylic C–H bond of the cyclopropane to provide the corresponding spirooxindole 44 in 60% yield (Scheme 13).
Intramolecular competition reactions investigated the chemoselectivity of the
Scheme 12 Proposed reaction mechanism for the synthesis of 3,3
0 -cyclopropyl spirooxindoles
Scheme 13 Takemoto’s synthesis of spirooxindoles and order of reactivity experiments
100
D. Sustac Roman and A.B. Charette