TY - JOUR
T1 - Direct enolization chemistry of 7-azaindoline amides
T2 - A case study of bis(tetrahydrophosphole)-type ligands
AU - Li, Zhao
AU - Noda, Hidetoshi
AU - Kumagai, Naoya
AU - Shibasaki, Masakatsu
N1 - Funding Information:
This work was financially supported by ACT-C ( JPMJCR12YO ) from JST, and KAKENHI ( 17H03025 and JP16H01043 in Precisely Designed Catalysts with Customized Scaffolding) from JSPS.
Publisher Copyright:
© 2018 Elsevier Ltd
PY - 2018/6/28
Y1 - 2018/6/28
N2 - 7-Azaindoline amides are particularly useful in direct enolization chemistry due to their facilitated enolization in soft Lewis acid/Brønsted base cooperative catalysis. The Cu(I) complex of (R,R)-Ph-BPE, a bis(tetrahydrophosphole)-type chiral bisphosphine ligand, exhibits consistently high catalytic performance and stereoselectivity irrespective of the nature of the α-substituent of the amides. Unexpectedly, however, alkyl-substituted bis(tetrahydrophosphole)-type ligands have substantially inferior catalytic performance. Evaluation of the optimized structures of Cu(I)/amide and Cu(I)/enolate complexes provided clues to dissecting the diverted reaction outcomes.
AB - 7-Azaindoline amides are particularly useful in direct enolization chemistry due to their facilitated enolization in soft Lewis acid/Brønsted base cooperative catalysis. The Cu(I) complex of (R,R)-Ph-BPE, a bis(tetrahydrophosphole)-type chiral bisphosphine ligand, exhibits consistently high catalytic performance and stereoselectivity irrespective of the nature of the α-substituent of the amides. Unexpectedly, however, alkyl-substituted bis(tetrahydrophosphole)-type ligands have substantially inferior catalytic performance. Evaluation of the optimized structures of Cu(I)/amide and Cu(I)/enolate complexes provided clues to dissecting the diverted reaction outcomes.
KW - Aldol reaction
KW - Asymmetric catalysis
KW - Copper
KW - Enolates
KW - Mannich reaction
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U2 - 10.1016/j.tet.2018.03.073
DO - 10.1016/j.tet.2018.03.073
M3 - Article
AN - SCOPUS:85045476735
SN - 0040-4020
VL - 74
SP - 3301
EP - 3305
JO - Tetrahedron
JF - Tetrahedron
IS - 26
ER -