posted on 2023-11-03, 17:04authored byYue Ma, Qing-Hui Liu, Ya-Ping Han
An
elegant Pd(dba)2-catalyzed enantioselective Heck
dearomative annulation of indoles and N-tosylhydrazones
for the straightforward assembly of structurally diverse optically
active indoline scaffolds containing the quaternary carbon centers
at the C2 position has been developed. The tandem protocol, which
utilized a Pd(dba)2/BINOL-based phosphoramidite ligand
as the catalytic system, proceeded smoothly through successive oxidative
addition, intramolecular carbon palladation, migratory insertion,
and β-elimination sequences, leading to the chiral indoline
derivatives in moderate to excellent yields, with excellent enantioselectivities
and diastereoselectivities. In addition, the synthetic practicability
of the catalytic system was underlined by a scaled-up experiment and
the late-stage derivatization of the products, thus highlighting the
potential applications in synthetic chemistry, medicinal chemistry,
and material science.