Response speed control of helicity inversion based on a “regulatory enzyme”-like strategy

In biological systems, there are many signal transduction cascades in which a chemical signal is transferred as a series of chemical events. Such successive reaction systems are advantageous because the efficiency of the functions can be finely controlled by regulatory enzymes at an earlier stage. However, most of artificial responsive molecules developed so far rely on single-step conversion, whose response speeds have been difficult to be controlled by external stimuli. In this context, developing artificial conversion systems that have a regulation step similar to the regulatory enzymes has been anticipated. Here we report a novel artificial two-step structural conversion system in which the response speed can be controlled based on a regulatory enzyme-like strategy. In this system, addition of fluoride ion caused desilylation of the siloxycarboxylate ion attached to a helical complex, resulting in the subsequent helicity inversion. The response speeds of the helicity inversion depended on the reactivity of the siloxycarboxylate ions; when a less-reactive siloxycarboxylate ion was used, the helicity inversion rate was governed by the desilylation rate. This is the first artificial responsive molecule in which the overall response speed can be controlled at the regulation step separated from the function step

Absolute Configuration Determination from Low ee Compounds by the Crystalline Sponge Method. Unusual Conglomerate Formation in a Pre-Determined Crystalline Lattice

When chiral compounds with low enantiomeric excess (ee, R:S=m:n) were absorbed into the void of the crystalline sponge (CS), enantiomerically pure [(R)m(S)n] chiral composites were formed, changing the centrosymmetric space group into non-centrosymmetric one. The absolute configuration of the analyte compounds was elucidated with a reasonable Flack (Parsons) parameter value. This phenomenon is characteristic to the “post-crystallization” in the pre-determined CS crystalline lattice, seldom found in common crystallization where the crystalline lattice is defined by an analyte itself. The results highlight the potential of the CS method for absolute configuration determination of low ee samples, an often encountered situation in asymmetric synthesis studies

CCDC 1810854: Experimental Crystal Structure Determination

Related Article: Ritesh Dubey, KaKing Yan, Takashi Kikuchi, Shiho Sairenji, Anouk Rossen, Shermin S. Goh, Ben L. Feringa, Makoto Fujita|2021|Angew.Chem.,Int.Ed.|60|11809|doi:10.1002/anie.20210255

CCDC 1810858: Experimental Crystal Structure Determination

Related Article: Ritesh Dubey, KaKing Yan, Takashi Kikuchi, Shiho Sairenji, Anouk Rossen, Shermin S. Goh, Ben L. Feringa, Makoto Fujita|2021|Angew.Chem.,Int.Ed.|60|11809|doi:10.1002/anie.20210255

CCDC 1810853: Experimental Crystal Structure Determination

Related Article: Ritesh Dubey, KaKing Yan, Takashi Kikuchi, Shiho Sairenji, Anouk Rossen, Shermin S. Goh, Ben L. Feringa, Makoto Fujita|2021|Angew.Chem.,Int.Ed.|60|11809|doi:10.1002/anie.20210255

CCDC 1810852: Experimental Crystal Structure Determination

Related Article: Ritesh Dubey, KaKing Yan, Takashi Kikuchi, Shiho Sairenji, Anouk Rossen, Shermin S. Goh, Ben L. Feringa, Makoto Fujita|2021|Angew.Chem.,Int.Ed.|60|11809|doi:10.1002/anie.20210255

CCDC 1810857: Experimental Crystal Structure Determination

Related Article: Ritesh Dubey, KaKing Yan, Takashi Kikuchi, Shiho Sairenji, Anouk Rossen, Shermin S. Goh, Ben L. Feringa, Makoto Fujita|2021|Angew.Chem.,Int.Ed.|60|11809|doi:10.1002/anie.20210255