Volume 9 Issue 10, October 2017

Volume 9 Issue 10

Tubingensin B is an indole diterpenoid that has a synthetically challenging chemical structure. Michael Corsello, Junyong Kim and Neil Garg from the University of California, Los Angeles, now report the total synthesis of this bioactive natural product. Their approach relies on the strategic use of a transient aryne intermediate — an aromatic ring containing a strained triple bond — to construct tubingensin B's pentacyclic core and highlights the utility of such long-avoided intermediates for the assembly of challenging structural motifs. The natural product's structure — underscored by the use of aryne intermediates in its synthesis — is stylized on the cover.Article p944IMAGE: DANIEL CASPI, ELEMENT TWENTYSIX

Commentary

  • Commentary |

    The question often arises as to who may have deserved a Nobel Prize but was not awarded one. Rarely is this discussion extended to who should have received more than one Nobel Prize, but in the field of organic synthesis there are some compelling candidates.

    • Jeffrey I. Seeman

News and Views

  • News & Views |

    Ejecting electrons from negative ions using light can create structures that very closely resemble the transition states of bimolecular reactions. Now, using this technique, trapped quantum states, or 'resonances', have been observed in a seven-atom reaction, and theory has been shown to be up to the task of capturing such complex phenomena.

    • Robert E. Continetti
  • News & Views |

    DNA double helical structures are supramolecular assemblies that are typically held together by classical Watson–Crick pairing. Now, nucleotide chelation of silver ions supports an extended silver–DNA hybrid duplex featuring an uninterrupted silver array.

    • Pascal Auffinger
    •  & Eric Ennifar
  • News & Views |

    Water is increasingly recognized as being of paramount importance in biological processes, yet its exact role remains difficult to elucidate. Now, the motion of water molecules within and around a synthetic peptide-amphiphile nanofibre has been precisely determined, showing significant differences between its core and surface.

    • Yoshimitsu Itoh
    •  & Takuzo Aida

Perspective

  • Perspective |

    Glucose-responsive insulin is a therapeutic that modulates its potency, concentration or dosing relative to a patient’s dynamic glucose concentration. This Perspective summarizes some of the recent accomplishments in this field as well as discussing new computational algorithms that may aid in the development of such therapeutics.

    • Naveed A. Bakh
    • , Abel B. Cortinas
    • , Michael A. Weiss
    • , Robert S. Langer
    • , Daniel G. Anderson
    • , Zhen Gu
    • , Sanjoy Dutta
    •  & Michael S. Strano

Articles

  • Article |

    The total synthesis of tubingensin B — an indole diterpenoid that bears a daunting chemical structure — has now been achieved. The design and evolution of this succinct total synthesis underscores the utility of long-avoided aryne intermediates for the introduction of structural motifs that have conventionally been viewed as challenging.

    • Michael A. Corsello
    • , Junyong Kim
    •  & Neil K. Garg
  • Article |

    The transition state governs how bonds form and cleave during a reaction — its direct characterization is a long-standing challenge. Now, the F + CH3OH → HF + CH3O reactive surface has been studied using photoelectron velocity-map imaging spectroscopy of cryo-cooled anions, revealing vibrational Feshbach resonances and bound states supported by the post-transition-state potential well. The experiments agree well with quantum dynamical calculations.

    • Marissa L. Weichman
    • , Jessalyn A. DeVine
    • , Mark C. Babin
    • , Jun Li
    • , Lifen Guo
    • , Jianyi Ma
    • , Hua Guo
    •  & Daniel M. Neumark
  • Article |

    A metallo–DNA hybrid nanowire composed only of silver-mediated base pairs has been prepared and its crystal structure resolved by X-ray diffraction. The nanowire, which is 2 nm wide and whose length reaches the μm to mm scale, holds silver ions into uninterrupted one-dimensional arrays along the DNA helical axis.

    • Jiro Kondo
    • , Yoshinari Tada
    • , Takenori Dairaku
    • , Yoshikazu Hattori
    • , Hisao Saneyoshi
    • , Akira Ono
    •  & Yoshiyuki Tanaka
  • Article |

    An enzyme (AspRedAm) capable of coupling carbonyls with a variety of amines in a reductive amination has now been discovered. Kinetic studies revealed that the enzyme catalysed both the imine formation step, as well as the reduction step. Structure and mutagenesis studies have highlighted essential catalytic residues and preparative scale examples have demonstrated total turnover numbers of up to 32,000.

    • Godwin A. Aleku
    • , Scott P. France
    • , Henry Man
    • , Juan Mangas-Sanchez
    • , Sarah L. Montgomery
    • , Mahima Sharma
    • , Friedemann Leipold
    • , Shahed Hussain
    • , Gideon Grogan
    •  & Nicholas J. Turner
  • Article |

    The asymmetric Doyle–Kirmse reaction using chiral Rh(II)- or Cu(I)-catalysts provides SCF3-containing compounds in a highly efficient and enantioselective manner. The reaction proceeds through enantioselective formation of sulfonium ylide from a diazoester and allyl- or propargyl trifluoromethyl sulfide, followed by concerted [2,3]-sigmatropic rearrangement with the transfer of chirality from sulfur to carbon.

    • Zhikun Zhang
    • , Zhe Sheng
    • , Weizhi Yu
    • , Guojiao Wu
    • , Rui Zhang
    • , Wen-Dao Chu
    • , Yan Zhang
    •  & Jianbo Wang
  • Article |

    Hexacoordinate silicon is seen often in molecular compounds, but very rarely in crystalline silicate materials. Now, reversible Si–O chemistry has been used to assemble octahedral dianionic SiO6 building units and anthracene derivatives into crystalline microporous silicate organic frameworks that share characteristics of both covalent organic frameworks and inorganic zeolites.

    • Jérôme Roeser
    • , Dragica Prill
    • , Michael J. Bojdys
    • , Pierre Fayon
    • , Abbie Trewin
    • , Andrew N. Fitch
    • , Martin U. Schmidt
    •  & Arne Thomas
  • Article |

    Singlet fission — converting a singlet exciton to two triplet excitons — may be useful for improving photovoltaic efficiency. Ultrafast spectroscopic measurements and quantum chemical calculations have now uncovered aspects of the process critical to it occurring efficiently, including the role of intermolecular vibrations and symmetry breaking, and the location of a conical intersection on the excited-state potential-energy surface.

    • Kiyoshi Miyata
    • , Yuki Kurashige
    • , Kazuya Watanabe
    • , Toshiki Sugimoto
    • , Shota Takahashi
    • , Shunsuke Tanaka
    • , Jun Takeya
    • , Takeshi Yanai
    •  & Yoshiyasu Matsumoto
  • Article |

    A DNA-based reaction network has now been developed that creates a French flag pattern with immobile and sharp borders from a shallow initial concentration gradient. The output pattern can be used to control the macroscopic organization of DNA-decorated particles thereby inducing a French flag pattern of colloidal aggregation.

    • Anton S. Zadorin
    • , Yannick Rondelez
    • , Guillaume Gines
    • , Vadim Dilhas
    • , Georg Urtel
    • , Adrian Zambrano
    • , Jean-Christophe Galas
    •  & André Estevez-Torres
  • Article |

    Cross coupling under transition-metal-free conditions is an attractive and economic alternative to traditional transition-metal-catalysed methods. Metal-free coupling of azaallyls has now been demonstrated with vinyl bromide electrophiles, delivering allylic amines in excellent yields. Moreover, mechanistic evidence supports dual reaction pathways triggered by azaallyl anions and radicals.

    • Minyan Li
    • , Osvaldo Gutierrez
    • , Simon Berritt
    • , Ana Pascual-Escudero
    • , Ahmet Yeşilçimen
    • , Xiaodong Yang
    • , Javier Adrio
    • , Georgia Huang
    • , Eiko Nakamaru-Ogiso
    • , Marisa C. Kozlowski
    •  & Patrick J. Walsh
  • Article |

    Uncovering the microscopic details of protein–protein association via direct molecular dynamics (MD) simulations has been prevented by the excessive lifetimes of associated states. Now, association and dissociation for the barnase–barstar complex has been studied by adaptive high-throughput MD simulations and Markov modelling, revealing intermediate structures, energetics and kinetics on microseconds-to-hours timescales.

    • Nuria Plattner
    • , Stefan Doerr
    • , Gianni De Fabritiis
    •  & Frank Noé
  • Article |

    The assembly–disassembly–organization–reassembly (ADOR) process has recently enabled the synthesis of unusual — and sometimes previously inaccessible — inorganic materials. Further insight into its complex mechanism has now been gained that explains the unexpected formation and structure of such a zeolite.

    • Samuel A. Morris
    • , Giulia P. M. Bignami
    • , Yuyang Tian
    • , Marta Navarro
    • , Daniel S. Firth
    • , Jiří Čejka
    • , Paul S. Wheatley
    • , Daniel M. Dawson
    • , Wojciech A. Slawinski
    • , David S. Wragg
    • , Russell E. Morris
    •  & Sharon E. Ashbrook
  • Article |

    It is still a great challenge to synthesize value-added products with two or more carbons directly from CO2. Now, a bifunctional catalyst composed of reducible metal oxides (In2O3) and zeolites (HZSM-5) is prepared and yields high selectivity to gasoline-range hydrocarbons (78.6%) with a high octane number directly from CO2 hydrogenation.

    • Peng Gao
    • , Shenggang Li
    • , Xianni Bu
    • , Shanshan Dang
    • , Ziyu Liu
    • , Hui Wang
    • , Liangshu Zhong
    • , Minghuang Qiu
    • , Chengguang Yang
    • , Jun Cai
    • , Wei Wei
    •  & Yuhan Sun
  • Article |

    Cancer stem cells are typically refractory to conventional treatments. Now, an unprecedented mechanism has been discovered by which salinomycin and derivatives can sequester iron in lysosomes leading to cytoplasmic iron depletion and the subsequent production of reactive oxygen species that are lethal to the cell. This discovery of the importance of iron in cancer stem cell maintenance provides an opportunity for developing new therapeutics.

    • Trang Thi Mai
    • , Ahmed Hamaï
    • , Antje Hienzsch
    • , Tatiana Cañeque
    • , Sebastian Müller
    • , Julien Wicinski
    • , Olivier Cabaud
    • , Christine Leroy
    • , Amandine David
    • , Verónica Acevedo
    • , Akihide Ryo
    • , Christophe Ginestier
    • , Daniel Birnbaum
    • , Emmanuelle Charafe-Jauffret
    • , Patrice Codogno
    • , Maryam Mehrpour
    •  & Raphaël Rodriguez

In Your Element

  • In Your Element |

    Dieter Ackermann explains why element 110 occupies a significant place in the superheavy corner of the periodic table.

    • Dieter Ackermann