Catalytic Enantioselective Dehydrogenative Si–O Coupling to Access Chiroptical Silicon-Stereogenic Siloxanes and Alkoxysilanes

Abstract

A rhodium-catalyzed enantioselective construction of triorgano-substituted silicon-stereogenic siloxanes and alkoxysilanes is developed. This process undergoes a direct intermolecular dehydrogenative Si–O coupling between dihydrosilanes with silanols or alocohols, giving access to a variety of highly functionalized chiral siloxanes and alkoxysilanes in decent yields with excellent stereocontrol, that significantly expand the chemical space of the silicon-centered chiral molecules. Further utility of this process was illustrated by the construction of CPL-active (circularly polarized luminescence) silicon-stereogenic alkoxysilane small organic molecules. Optically pure bis-alkoxysilane containing two silicon-stereogenic centers and three pyrene groups displayed a remarkable g lum value with a high fluorescence quantum efficiency (g lum = 0.011, ΦF = 0.55), which could have great potential application prospects in chiral organic optoelectronic materials.

Catalytic Asymmetric Homologation of 4‐Substituted Cyclohexanones with CF3CHN2: Enantioselective Synthesis of α‐Trifluoromethyl Cycloheptanones

“…Thus, we further conceived that a chiral silicon center might be constructed by replacing the γ‐carbon with silicon. Construction of chiral silicon centers has attracted considerable interests in recent years, while desymmetrization is the most effective catalytic asymmetric strategy to access a silicon‐stereogenic center in an enantioselective manner [33–35] . Thus, we proceeded to examine the scope of silacyclohexanones.…”

CPL on/off control of an assembled system by water soluble macrocyclic chiral sources with planar chirality

“… 5 In general, the fabrication of CPL materials can be achieved by two strategies. The first involves covalently connecting the chiral and fluorescent units to generate chiral luminescent small molecules 6 or polymers 7 and their assemblies. 8 This results in the two units being close together and enables the systems to possess relatively high dissymmetry values (| g lum |).…”

Catalytic Enantioselective Construction of Chiroptical Boron-Stereogenic Compounds

“…Recently, we have developed a number of catalytic desymmetric approaches for the construction of silicon- and sulfur-stereogenic centers with high efficiency and enantioselectivity. − With the continued interest in the synthesis of heteroatom-stereogenic compounds, we questioned whether we could develop a catalytic enantioselective process for the construction of boron-stereogenic centers via desymmetrization of tetracoordinate boron compounds. To achieve this target, the choice of suitable coordinated ligands around the boron atom and the identification of an appropriate catalytic desymmetric reaction are crucial.…”