Four-Step Domino Reaction Enables Fully Controlled Non-Statistical Synthesis of Hexaarylbenzene with Six Different Aryl Groups*

Hexaarylbenzene (HAB) derivatives are versatile aromatic systems playing a significant role as chromophores, liquid crystalline materials, molecular receptors, molecular-scale devices, organic light-emitting diodes and candidates for organic electronics. Statistical synthesis of simple symmetrical HABs is known via cyclotrimerization or Diels–Alder reactions. By contrast, the synthesis of more complex, asymmetrical systems, and without involvement of statistical steps, remains an unsolved problem. Here we present a generally applicable synthetic strategy to access asymmetrical HAB via an atom-economical and high-yielding metal-free four-step domino reaction using nitrostyrenes and α,α-dicyanoolefins as easily available starting materials. Resulting domino product—functionalized triarylbenzene (TAB)—can be used as a key starting compound to furnish asymmetrically substituted hexaarylbenzenes in high overall yield and without involvement of statistical steps. This straightforward domino process represents a distinct approach to create diverse and still unexplored HAB scaffolds, containing six different aromatic rings around central benzene core. © 2021 The Authors. Angewandte Chemie International Edition published by Wiley-VCH Gmb

Electron Microscopy Of Wood Of Callixylon And Cordaites

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141638/1/ajb210693.pd

Musty-earthy scent in cactus flowers: Characteristics of floral scent production in dehydrogeosmin-producing cacti

The musty-earthy-smelling sesquiterpenoid dehydrogeosmin (DHG) was found several years ago as a novel compound in flowers of some cactus species, which called attention to the biology of floral scents of the Cactaceae. Our studies showed that the odor

Aryl Hydrocarbon Receptor Is Critical for Homeostasis of Invariant gamma delta T Cells in the Murine Epidermis

An immunoregulatory role of aryl hydrocarbon receptor (AhR) has been shown in conventional alpha beta and gamma delta T cells, but its function in skin gamma delta T cells (dendritic epidermal T cells [DETC]) is unknown. In this study, we demonstrate that DETC express AhR in wildtype mice, and are specifically absent in the epidermis of AhR-deficient mice (AhR-KO). We show that DETC precursors are generated in the thymus and home to the skin. Proliferation of DETC in the skin was impaired in AhR-KO mice, resulting in a >90% loss compared with wild type. Surprisingly, DETC were not replaced by alpha beta T cells or conventional gamma delta T cells, suggesting a limited time frame for seeding this niche. We found that DETC from AhR-KO mice failed to express the receptor tyrosine kinase c-Kit, a known growth factor for gamma delta T cells in the gut. Moreover, we found that c-kit is a direct target of AhR, and propose that AhR-dependent c-Kit expression is potentially involved in DETC homeostasis. DETC are a major source of GM-CSF in the skin. Recently, we had shown that impaired Langerhans cell maturation in AhR-KO is related to low GM-CSF levels. Our findings suggest that the DETCs are necessary for LC maturation, and provide insights into a novel role for AhR in the maintenance of skin-specific gamma delta T cells, and its consequences for the skin immune network. The Journal of Immunology, 2011, 187: 3104-3110

Metal-Free Four-Step Domino Reaction Enables Fully Controlled Non-Statistical Synthesis of Hexaarylbenzene with Six Different Aryl Groups

Hexaarylbenzene (HAB) derivatives are versatile aromatic systems playing a significant role as chromophores, liquid crystalline materials, molecular receptors, redox materials, organic light-emitting diodes and photochemical switches. Statistical synthesis of simple symmetrical HABs is known via low-yielding cyclotrimerization or Diels-Alder reactions. By contrast, the synthesis of more complex, asymmetrical systems, and without involvement of statistical steps, remains an unsolved problem. Here we present a generally applicable synthetic strategy to access asymmetrical HAB via an atom-economical and high-yielding metal-free four-step domino reaction using nitrostyrenes and α,α-dicyanoolefins as easily available starting materials. Resulting domino product – functionalized triarylbenzene (TAB) - can be used as a key starting compound to furnish asymmetrically substituted hexaarylbenzenes in high overall yield and without involvement of statistical steps. This straightforward domino process represents a distinct approach to creating diverse and still unexplored HAB scaffolds, containing six different aromatic rings around central benzene core

Four‐step domino reaction enables fully controlled non‐statistical synthesis of hexaarylbenzene with six different aryl groups

Hexaarylbenzene (HAB) derivatives are versatile aromatic systems playing a significant role as chromophores, liquid crystalline materials, molecular receptors, molecular‐scale devices, organic light‐emitting diodes and candidates for organic electronics. Statistical synthesis of simple symmetrical HABs is known via cyclotrimerization or Diels–Alder reactions. By contrast, the synthesis of more complex, asymmetrical systems, and without involvement of statistical steps, remains an unsolved problem. Here we present a generally applicable synthetic strategy to access asymmetrical HAB via an atom‐economical and high‐yielding metal‐free four‐step domino reaction using nitrostyrenes and α,α‐dicyanoolefins as easily available starting materials. Resulting domino product—functionalized triarylbenzene (TAB)—can be used as a key starting compound to furnish asymmetrically substituted hexaarylbenzenes in high overall yield and without involvement of statistical steps. This straightforward domino process represents a distinct approach to create diverse and still unexplored HAB scaffolds, containing six different aromatic rings around central benzene core