Catalytic Asymmetric Bromocyclization of Polyenes

Journal of the American Chemical Society, Journal Year: 2017, Volume and Issue: 139(4), P. 1460 - 1463

Published: Jan. 6, 2017

The first catalytic asymmetric bromonium ion-induced polyene cyclization has been achieved by using a chiral BINOL-derived thiophosphoramide catalyst and 1,3-dibromo-5,5-dimethylhydantoin as an electrophilic bromine source. Bromocyclization products are obtained in high yields, with good enantiomeric ratios diastereoselectivity, abundantly found scaffolds natural products.

Language: Английский

---

Halogenation of organic compounds using continuous flow and microreactor technology

Reaction Chemistry & Engineering, Journal Year: 2016, Volume and Issue: 2(1), P. 7 - 19

Published: Nov. 17, 2016

Halogenation reactions involving highly reactive halogenating agents can be performed safely and with improved efficiency selectivity under continuous flow conditions.

Language: Английский

---

Catalytic Enantioselective Dihalogenation in Total Synthesis

Accounts of Chemical Research, Journal Year: 2018, Volume and Issue: 51(5), P. 1260 - 1271

Published: April 17, 2018

ConspectusTo date, more than 5000 biogenic halogenated molecules have been characterized. This number continues to increase as chemists explore chloride- and bromide-rich marine environments in search of novel bioactive natural products. Naturally occurring organohalogens span nearly all biosynthetic structural classes, exhibit a range unique biological activities, the subject numerous investigations. Despite abundance interest molecules, enantioselective methods capable forging carbon–halogen bonds synthetically relevant contexts remain scarce. Accordingly, syntheses often rely on multistep functional group interconversions establish stereocenters. Our has developed an dihalogenation reaction utilized it only reported examples catalytic halogenation product synthesis. In this Account, we describe our laboratory's development method for catalytic, application synthesis both mono- polyhalogenated first part, initial discovery TADDOL-mediated dibromination cinnamyl alcohols. Extension second-generation system selective bromochlorination, dichlorination, is then detailed. controlling enantioselectivity dihalide formation, chemoselectivity polyolefinic substrates, regioselectivity case bromochlorination. The ability exert control over halide delivery permits electronically nonbiased olefins required total synthesis.In second demonstrate how described provided efficient access host structurally diverse most direct methodology naturally vicinal dihalides. Chiral bromochlorides represent class >175 products; five members class, including its flagship member, (+)-halomon, accomplished through use Likewise, dichlorination two chlorosulfolipids, linear, acyclic polychlorides. Synthesis chiral monohalides achieved solvolysis enantioenriched bromochlorides; approach resulted bromocyclohexane-containing products enantiospecific bromopolyene cyclization. reviewing these syntheses, framework mediated by emerged.The highly enabling detail encourage further useful methodologies.

Language: Английский

---

Chlorinated Solvents: Their Advantages, Disadvantages, and Alternatives in Organic and Medicinal Chemistry

Chemical Reviews, Journal Year: 2020, Volume and Issue: 121(3), P. 1582 - 1622

Published: Dec. 22, 2020

Chlorinated solvents were once, and in many places are still, ubiquitous chemistry laboratories. This review explores the properties that led to such widespread use, why there is now an increasing drive minimize usage, what alternatives currently available.

Language: Английский

---

Triptycenyl Sulfide: A Practical and Active Catalyst for Electrophilic Aromatic Halogenation Using N-Halosuccinimides

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 142(3), P. 1621 - 1629

Published: Dec. 23, 2019

A Lewis base catalyst Trip-SMe (Trip = triptycenyl) for electrophilic aromatic halogenation using N-halosuccinimides (NXS) is introduced. In the presence of an appropriate activator (as a noncoordinating-anion source), series unactivated compounds were halogenated at ambient temperature NXS. This catalytic system was applicable to transformations that are currently unachievable except use Br2 or Cl2: e.g., multihalogenation naphthalene, regioselective bromination BINOL, etc. Controlled experiments revealed triptycenyl substituent exerts crucial role activity, and kinetic implied occurrence sulfonium salt [Trip-S(Me)Br][SbF6] as active species. Compared simple dialkyl sulfides, exhibited significant charge-separated ion pair character within halonium complex whose structural information obtained by single-crystal X-ray analysis. preliminary computational study disclosed π functionality key motif consolidate enhancement electrophilicity.

Language: Английский

---

Visible‐Light‐Induced Vicinal Dichlorination of Alkenes through LMCT Excitation of CuCl₂

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(52), P. 23603 - 23608

Published: Sept. 14, 2020

Abstract This work demonstrates photoredox vicinal dichlorination of alkenes, based on the homolysis CuCl 2 in response to irradiation with visible light. catalysis proceeds via a ligand metal charge transfer process and provides an exciting opportunity for synthesis 1,2‐dichloride compounds using inexpensive, low‐molecular‐weight chlorine source. new exhibits wide substrate scope, excellent functional group tolerance, extraordinarily mild conditions does not require external ligands. Mechanistic studies show that ready formation atom radicals is responsible facile C−Cl bonds this synthetic process.

Language: Английский

---

Catalytic Enantioselective Dihalogenation and the Selective Synthesis of (−)-Deschloromytilipin A and (−)-Danicalipin A

Journal of the American Chemical Society, Journal Year: 2016, Volume and Issue: 138(15), P. 5150 - 5158

Published: March 28, 2016

A titanium-based catalytic enantioselective dichlorination of simple allylic alcohols is described. This reaction provides stereoselective access to all common dichloroalcohol building blocks used in syntheses chlorosulfolipid natural products. An synthesis ent-(-)-deschloromytilipin and a concise, eight-step ent-(-)-danicalipin are executed employ the as first step. Extension this system dibromination its use pentabromide stereoarrays relevant bromosulfolipids reported. The described reactions capable exerting diastereocontrol complex settings allowing X-ray crystal structure analysis unnatural diastereomers polyhalogenated stereohexads.

Language: Английский

---

Sustainable metal catalysis in C H activation

Coordination Chemistry Reviews, Journal Year: 2017, Volume and Issue: 343, P. 25 - 138

Published: May 5, 2017

Language: Английский

---

NXS, Morpholine, and HFIP: The Ideal Combination for Biomimetic Haliranium-Induced Polyene Cyclizations

Journal of the American Chemical Society, Journal Year: 2018, Volume and Issue: 140(12), P. 4344 - 4353

Published: Feb. 7, 2018

In contrast to Nature that accomplishes polyene cyclizations seemingly with ease, such transformations are difficult conduct in the lab. our program dealing development of selective halogenations alkenes, we now asserted standard X+ reagents perfectly suited for biomimetic cation-π cyclization both electron rich and poor linear polyenes presence Lewis base morpholine acid HFIP. The method stands out due its broad substrate scope practicability together high chemical yields excellent selectivities, even highly challenging chloriranium-induced cyclizations.

Language: Английский

---

Functional Enzyme Mimics for Oxidative Halogenation Reactions that Combat Biofilm Formation

Advanced Materials, Journal Year: 2018, Volume and Issue: 30(36)

Published: June 19, 2018

Abstract Transition‐metal oxide nanoparticles and molecular coordination compounds are highlighted as functional mimics of halogenating enzymes. These enzymes involved in halometabolite biosynthesis. Their activity is based upon the formation hypohalous acids from halides hydrogen peroxide or oxygen, which form bioactive secondary metabolites microbial origin with strong antibacterial antifungal activities follow‐up reactions. Therefore, enzyme may be valuable tools to combat biofilm formation. Here, models briefly described, classified according their catalytic functions, current knowledge about settlement chemistry adhesion fouling organisms summarized. Enzyme highest potential showcased. They find application antifouling coatings, indoor outdoor paints, polymer membranes for water desalination, aquacultures, but also on surfaces food packaging, door handles, hand rails, push buttons, keyboards, other elements made plastic where biofilms present. The use natural compounds, formed situ nontoxic abundant metal mimics, represents a novel efficient “green” strategy emulate utilize defense system preventing bacterial colonization growth.

Language: Английский

---