Abstract:
:This study introduces new methods of screening for and tuning chiral space and in so doing identifies a promising set of chiral ligands for asymmetric synthesis. The carbafructopyranosyl-1,2-diamine(s) and salens constructed therefrom are particularly compelling. It is shown that by removing the native anomeric effect in this ligand family, one can tune chiral ligand shape and improve chiral bias. This concept is demonstrated by a combination of (i) x-ray crystallographic structure determination, (ii) assessment of catalytic performance, and (iii) consideration of the anomeric effect and its underlying dipolar basis. The title ligands were identified by a new mini version of the in situ enzymatic screening (ISES) procedure through which catalyst-ligand combinations are screened in parallel, and information on relative rate and enantioselectivity is obtained in real time, without the need to quench reactions or draw aliquots. Mini-ISES brings the technique into the nanomole regime (200 to 350 nmol catalyst/20 μml organic volume) commensurate with emerging trends in reaction development/process chemistry. The best-performing β-d-carbafructopyranosyl-1,2-diamine-derived salen ligand discovered here outperforms the best known organometallic and enzymatic catalysts for the hydrolytic kinetic resolution of 3-phenylpropylene oxide, one of several substrates examined for which the ligand is "matched." This ligand scaffold defines a new swath of chiral space, and anomeric effect tunability defines a new concept in shaping that chiral space. Both this ligand set and the anomeric shape-tuning concept are expected to find broad application, given the value of chiral 1,2-diamines and salens constructed from these in asymmetric catalysis.
journal_name
Sci Advjournal_title
Science advancesauthors
Karukurichi KR,Fei X,Swyka RA,Broussy S,Shen W,Dey S,Roy SK,Berkowitz DBdoi
10.1126/sciadv.1500066subject
Has Abstractpub_date
2015-07-01 00:00:00issue
6issn
2375-2548journal_volume
1pub_type
杂志文章相关文献
Science Advances文献大全abstract::To achieve global elimination of hepatitis C virus (HCV), an effective cross-genotype vaccine is needed. The HCV envelope glycoprotein E2 is the main target for neutralizing antibodies (nAbs), which aid in HCV clearance and protection. E2 is structurally flexible and functions in engaging host receptors. Many nAbs bin...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.abb5642
更新日期:2020-07-24 00:00:00
abstract::We examine the low-temperature states supported by the quasiperiodic host-guest structure of elemental bismuth at high pressure, Bi-III. Our electronic transport and magnetization experiments establish Bi-III as a rare example of type II superconductivity in an element, with a record upper critical field of ~ 2.5 T, u...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.aao4793
更新日期:2018-04-13 00:00:00
abstract::We describe an approach to print composite polymers in high-resolution three-dimensional (3D) architectures that can be rapidly transformed to a new permanent configuration directly by heating. The permanent shape of a component results from the programmed time evolution of the printed shape upon heating via the desig...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.1602890
更新日期:2017-04-12 00:00:00
abstract::Although Al(III) hydrolysis, condensation, and nucleation play pivotal roles in the synthesis of Al-based compounds and determine their chemical behavior, we still lack experimental evidence regarding the chemistry of nucleation from solution. Here, by combining advanced titration assays, high-resolution transmission ...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.aba6878
更新日期:2020-06-03 00:00:00
abstract::In 2015, more than 200,000 saiga antelopes died in 3 weeks in central Kazakhstan. The proximate cause of death is confirmed as hemorrhagic septicemia caused by the bacterium Pasteurella multocida type B, based on multiple strands of evidence. Statistical modeling suggests that there was unusually high relative humidit...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.aao2314
更新日期:2018-01-17 00:00:00
abstract::Topological superconductors are exotic phases of matter featuring robust surface states that could be leveraged for topological quantum computation. A useful guiding principle for the search of topological superconductors is to relate the topological invariants with the behavior of the pairing order parameter on the n...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.aaz8367
更新日期:2020-05-01 00:00:00
abstract::Arthropod herbivores cause substantial economic costs that drive an increasing need to develop environmentally sustainable approaches to herbivore control. Increasing plant diversity is expected to limit herbivory by altering plant-herbivore and predator-herbivore interactions, but the simultaneous influence of these ...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.abb6603
更新日期:2020-11-06 00:00:00
abstract::We analyze a collection of empirical networks in a wide spectrum of disciplines and show that strong non-normality is ubiquitous in network science. Dynamical processes evolving on non-normal networks exhibit a peculiar behavior, as initial small disturbances may undergo a transient phase and be strongly amplified in ...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.aau9403
更新日期:2018-12-12 00:00:00
abstract::Carbon deposits are well-known inhibitors of transition metal catalysts. In contrast to this undesirable behavior, here we show that epitaxial graphene grown on Ru(0001) promotes the reversible formation of a C-C bond between -CH2CN and 7,7,8,8-tetracyano-p-quinodimethane (TCNQ). The catalytic role of graphene is mult...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.aau9366
更新日期:2018-12-14 00:00:00
abstract::Engineered surfaces with reversibly switching interfacial properties, such as wettability and liquid repellency, are highly desirable in diverse application fields but are rare. We have developed a general concept to prepare metallic porous surfaces with exceptionally powerful wettability switch capabilities and liqui...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.aax0380
更新日期:2019-11-01 00:00:00
abstract::Electrochemical analysis of sweat using soft bioelectronics on human skin provides a new route for noninvasive glucose monitoring without painful blood collection. However, sweat-based glucose sensing still faces many challenges, such as difficulty in sweat collection, activity variation of glucose oxidase due to lact...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.1601314
更新日期:2017-03-08 00:00:00
abstract::Using a national longitudinal survey data set from the Higher Education Research Institute, this study tested whether students who identified as a sexual minority (for example, lesbian, gay, bisexual, or queer) were more or less likely to persist after 4 years in science, technology, engineering, and mathematics (STEM...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.aao6373
更新日期:2018-03-14 00:00:00
abstract::Immotile cilia sense extracellular signals such as fluid flow, but whether Ca2+ plays a role in flow sensing has been unclear. Here, we examined the role of ciliary Ca2+ in the flow sensing that initiates the breaking of left-right (L-R) symmetry in the mouse embryo. Intraciliary and cytoplasmic Ca2+ transients were d...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.aba1195
更新日期:2020-07-22 00:00:00
abstract::Multicellular organisms are composed of tissues that have distinct functions requiring specialized proteomes. To define the proteome of a live animal with tissue and subcellular resolution, we adapted a localized proteomics technology for use in the multicellular model organism Caenorhabditis elegans. This approach co...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.1602426
更新日期:2017-05-10 00:00:00
abstract::Skyrmions are topologically protected nanoscale magnetic spin entities in helical magnets. They behave like particles and tend to form hexagonal close-packed lattices, like atoms, as their stable structure. Domain boundaries in skyrmion lattices are considered to be important as they affect the dynamic properties of m...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.1501280
更新日期:2016-02-12 00:00:00
abstract::Compound climate extremes are receiving increasing attention because of their disproportionate impacts on humans and ecosystems. However, risks assessments generally focus on univariate statistics. We analyze the co-occurrence of hot and dry summers and show that these are correlated, inducing a much higher frequency ...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.1700263
更新日期:2017-06-28 00:00:00
abstract::A withdrawal-associated impairment in β-endorphin neurotransmission in the arcuate nucleus (ARC) of the hypothalamus is associated with alcohol dependence characterized by a chronic relapsing disorder. Although acupuncture activates β-endorphin neurons in the ARC projecting to the nucleus accumbens (NAc), a role for A...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.aax1342
更新日期:2019-09-04 00:00:00
abstract::The basic physics of earthquakes is such that strong ground motion cannot be expected from an earthquake unless the earthquake itself is very close or has grown to be very large. We use simple seismological relationships to calculate the minimum time that must elapse before such ground motion can be expected at a dist...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.aaq0504
更新日期:2018-03-21 00:00:00
abstract::RNA interference (RNAi) technology can specifically silence the expression of a target gene and has emerged as a promising therapeutic method to treat cancer. In the present study, we showed that natural halloysite nanotube (HNT)-assisted delivery of an active small interfering RNA (siRNA) targeting receptor-interacti...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.aaw6499
更新日期:2019-09-25 00:00:00
abstract::Amorphous solids, such as glasses, have complex responses to deformations, with substantial consequences in material design and applications. In this respect, two intertwined aspects are important: stability and reversibility. It is crucial to understand, on the one hand, how a glass may become unstable due to increas...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.aat6387
更新日期:2018-12-07 00:00:00
abstract::Iron deficiency and anemia are prominent contributors to the preventable disease burden worldwide. A substantial proportion of people with inadequate dietary iron rely on rice as a staple food, but fortification efforts are limited by low iron bioavailability. Furthermore, using high iron fortification dosages may not...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.aau0790
更新日期:2019-03-27 00:00:00
abstract::The hydrogen atom-the smallest and most abundant atom-is of utmost importance in physics and chemistry. Although many analysis methods have been applied to its study, direct observation of hydrogen atoms in a single molecule remains largely unexplored. We use atomic force microscopy (AFM) to resolve the outermost hydr...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.1603258
更新日期:2017-05-12 00:00:00
abstract::Plants produce a myriad of taxonomically restricted specialized metabolites. This diversity-and our ability to correlate genotype with phenotype-makes the evolution of these ecologically and medicinally important compounds interesting and experimentally tractable. Trichomes of tomato and other nightshade family plants...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.aaw3754
更新日期:2019-04-24 00:00:00
abstract::Soft robotics may enable many new technologies in which humans and robots physically interact, yet the necessary high-performance soft actuators still do not exist. The optimal soft actuators need to be fast and forceful and have programmable shape changes. Furthermore, they should be energy efficient for untethered a...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.aay0855
更新日期:2019-11-22 00:00:00
abstract::The ability of a material to adopt multiple structures, known as polymorphism, is a fascinating natural phenomenon. Various polymorphs with unusual properties are routinely synthesized by compression under positive pressure. However, changing a material's structure by applying tension under negative pressure is much m...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.aaq1442
更新日期:2018-04-20 00:00:00
abstract::Understanding how surfaces direct nucleation is a complex problem that limits our ability to predict and control crystal formation. We here address this challenge using high-speed imaging to identify and quantify the sites at which ice nucleates in water droplets on the two natural cleavage faces of macroscopic feldsp...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.aav4316
更新日期:2019-02-01 00:00:00
abstract::Mucoadhesive particles (MAP) have been widely explored for pulmonary drug delivery because of their perceived benefits in improving particle residence in the lungs. However, retention of particles adhesively trapped in airway mucus may be limited by physiologic mucus clearance mechanisms. In contrast, particles that a...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.1601556
更新日期:2017-04-05 00:00:00
abstract::Several forms of hair loss in humans are characterized by the inability of hair follicles to enter the growth phase (anagen) of the hair cycle after being arrested in the resting phase (telogen). Current pharmacologic therapies have been largely unsuccessful in targeting pathways that can be selectively modulated to i...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.1500973
更新日期:2015-10-23 00:00:00
abstract::We tested how sediment trapping by hydroelectric dams affects tropical estuaries by comparing two dammed and two undammed rivers on Mexico's Pacific coast. We found that dams demonstrably affected the stability and productivity of the estuaries. The two rivers dammed for hydroelectricity had a rapid coastal recession ...
journal_title:Science advances
pub_type: 杂志文章
doi:10.1126/sciadv.aau9875
更新日期:2019-03-13 00:00:00
abstract::Over the past decade, a growing number of studies have revealed that progressive changes to epigenetic information accompany aging in both dividing and nondividing cells. Functional studies in model organisms and humans indicate that epigenetic changes have a huge influence on the aging process. These epigenetic chang...
journal_title:Science advances
pub_type: 杂志文章,评审
doi:10.1126/sciadv.1600584
更新日期:2016-07-29 00:00:00