title: A dramatic synergistic effect of a flexible achiral linker on a rigid chiral cis-1,2-diamine bifunctional organocatalyst.
abstract: The combination of a "rigid" chiral bicyclic cis-1,2-diamine skeleton with steric bulkiness and a "flexible" achiral linker was newly designed as a bifunctional organocatalyst framework and it showed excellent catalytic activity of up to 0.05 mol%, accompanied by the reversal of enantioselection depending on the position of the linker, in an amine-thiourea organocatalyzed asymmetric Michael reaction.
authors.affiliation: Faculty of Life Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan. mtc@gpo.kumamoto-u.ac.jp tstone@gpo.kumamoto-u.ac.jp.
authors.forename: Hirofumi
authors.identifier: http://orcid.org/0000-0001-7564-7720
authors.initials: H
authors.lastname: Matsunaga
authors.affiliation: Faculty of Life Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan. mtc@gpo.kumamoto-u.ac.jp tstone@gpo.kumamoto-u.ac.jp.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Tajima
authors.affiliation: Faculty of Life Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan. mtc@gpo.kumamoto-u.ac.jp tstone@gpo.kumamoto-u.ac.jp.
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Kawauchi
authors.affiliation: Faculty of Life Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan. mtc@gpo.kumamoto-u.ac.jp tstone@gpo.kumamoto-u.ac.jp.
authors.forename: Takuro
authors.initials: T
authors.lastname: Yasuyama
authors.affiliation: Faculty of Life Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan. mtc@gpo.kumamoto-u.ac.jp tstone@gpo.kumamoto-u.ac.jp.
authors.forename: Shin
authors.initials: S
authors.lastname: Ando
authors.affiliation: Faculty of Life Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan. mtc@gpo.kumamoto-u.ac.jp tstone@gpo.kumamoto-u.ac.jp.
authors.forename: Tadao
authors.initials: T
authors.lastname: Ishizuka