title: Direct Catalytic Asymmetric Mannich-type Reaction of α,β-Unsaturated γ-Butyrolactam with Ketimines.
abstract: We report a direct catalytic asymmetric Mannich-type addition of α,β-unsaturated γ-butyrolactam to α-ethoxycarbonyl ketimines promoted by a soft Lewis acid/Brønsted base cooperative catalyst. A thiophosphinoyl group on the nitrogen of ketimines was crucial for both electrophilic activation and α-addition of γ-butyrolactams. The obtained aza-Morita-Baylis-Hillman-type products bear an α-amino acid architecture with a tetra-substituted stereogenic center.
authors.affiliation: Institute of Microbial Chemistry (BIKAKEN), Tokyo, 3-14-23 Kamiosaki, Shinagawa-ku, Tokyo, 141-0021, Japan.
authors.forename: Shaoquan
authors.initials: S
authors.lastname: Lin
authors.affiliation: Institute of Microbial Chemistry (BIKAKEN), Tokyo, 3-14-23 Kamiosaki, Shinagawa-ku, Tokyo, 141-0021, Japan. mshibasa@bikaken.or.jp.
authors.forename: Naoya
authors.initials: N
authors.lastname: Kumagai
authors.affiliation: Institute of Microbial Chemistry (BIKAKEN), Tokyo, 3-14-23 Kamiosaki, Shinagawa-ku, Tokyo, 141-0021, Japan. nkumagai@bikaken.or.jp.
authors.forename: Masakatsu
authors.initials: M
authors.lastname: Shibasaki
keywords: amino acids; asymmetric catalysis; cooperative effects; ketimines; lactams