8-Bromo-3,4-dihydronaphthalen-2(1H)-one: Properties & Applications
8-Bromo-3,4-dihydronaphthalen-2(1H)-one: Properties & Applications
8-Bromo-3,4-dihydronaphthalen-2(1H)-one is a brominated bicyclic ketone that serves as a valuable synthetic building block and intermediate in organic and medicinal chemistry research.
- IUPAC Name
- 8-Bromo-3,4-dihydronaphthalen-2(1H)-one
- Core Scaffold
- Tetralone (3,4-dihydronaphthalen-2(1H)-one) with bromine substituent at the 8-position
- Functional Groups
- Aryl bromide, aliphatic ketone
- Primary Use
- Synthetic intermediate and building block for cross-coupling and further functionalization reactions
- Aladdin SKU
- B709046
- Reactivity Handles
- C–Br bond amenable to palladium-catalyzed cross-coupling; ketone amenable to nucleophilic addition, reductive amination, and enolate chemistry
Chemical Structure and Key Properties
8-Bromo-3,4-dihydronaphthalen-2(1H)-one belongs to the tetralone family of compounds, featuring a bicyclic framework composed of a benzene ring fused to a saturated six-membered ring containing a ketone carbonyl group. The bromine atom is positioned at the 8-position of the aromatic ring, which is ortho to the ring fusion carbon. This specific regiochemistry is chemically significant: the periplanar relationship between the bromine substituent and the adjacent aliphatic ring can influence both the conformational behavior of the molecule and the selectivity of subsequent reactions.
The molecule possesses two principal reactive sites: the aryl C–Br bond and the carbonyl group. The aryl bromide is electrophilic at the carbon center and is well-suited to oxidative addition into low-valent transition metal catalysts, making it highly amenable to palladium- and nickel-catalyzed cross-coupling protocols. The ketone carbonyl undergoes classical carbonyl chemistry including nucleophilic addition, Wittig olefination, reductive amination, and enolate alkylation, providing multiple vectors for structural diversification.
Synthesis and Functionalization Strategies
The tetralone skeleton is a well-established scaffold in organic synthesis, and brominated derivatives such as 8-Bromo-3,4-dihydronaphthalen-2(1H)-one are typically accessible via electrophilic aromatic bromination of the parent 3,4-dihydronaphthalen-2(1H)-one (β-tetralone) under controlled conditions, or through directed ortho-metalation and quenching with electrophilic bromine sources. Regioselective introduction of the bromine at the 8-position can also be achieved through substrate-directed approaches.
Once in hand, the compound can be elaborated through several convergent strategies. The aryl bromide participates readily in Suzuki–Miyaura, Negishi, Stille, Sonogashira, and Buchwald–Hartwig coupling reactions, enabling the introduction of aryl, alkenyl, alkynyl, and amino groups on the aromatic ring. Concurrently, the ketone may be manipulated independently, allowing sequential or orthogonal functionalization. This dual reactivity renders 8-Bromo-3,4-dihydronaphthalen-2(1H)-one a particularly flexible platform for the rapid construction of structurally complex bicyclic and polycyclic frameworks.
Research and Medicinal Chemistry Applications
Tetralone-based scaffolds are prominent in medicinal chemistry owing to their structural similarity to naturally occurring terpenoids, steroids, and biologically active alkaloids. The introduction of a halogen substituent, particularly bromine, at a defined position significantly expands synthetic access to analogue libraries through transition-metal-catalyzed diversification. Brominated tetralones such as 8-Bromo-3,4-dihydronaphthalen-2(1H)-one are therefore widely employed as key intermediates in the preparation of pharmacologically relevant target molecules.
Compounds derived from the tetralone scaffold have been investigated in the context of central nervous system (CNS) pharmacology, enzyme inhibition studies, and the synthesis of natural product analogues. The reactive aryl bromide in 8-Bromo-3,4-dihydronaphthalen-2(1H)-one provides a reliable handle for late-stage diversification, enabling medicinal chemists to efficiently explore structure–activity relationships (SAR) around the bicyclic core. The compound also finds utility in materials chemistry and as a precursor in the synthesis of ligands for coordination chemistry.
Handling, Storage, and Safety Considerations
As with all organobromine compounds and aryl ketones, 8-Bromo-3,4-dihydronaphthalen-2(1H)-one should be handled with appropriate laboratory precautions. Standard personal protective equipment (PPE), including nitrile gloves, safety glasses, and a laboratory coat, should be worn at all times when handling this compound. Operations generating dust or aerosols should be conducted in a well-ventilated fume hood.
For storage, the compound should be kept in a tightly sealed container, protected from light and moisture, and stored at a cool, dry location consistent with general guidance for halogenated organic solids. Users should consult the Safety Data Sheet (SDS) provided by Aladdin Scientific for comprehensive hazard information, first-aid measures, disposal guidance, and transport classifications before use. Waste disposal must comply with all applicable local, national, and institutional regulations governing halogenated organic waste.
Frequently asked questions
What is 8-Bromo-3,4-dihydronaphthalen-2(1H)-one used for in organic synthesis?
8-Bromo-3,4-dihydronaphthalen-2(1H)-one is primarily used as a bifunctional synthetic building block. Its aryl C–Br bond is compatible with palladium-catalyzed cross-coupling reactions (e.g., Suzuki–Miyaura, Buchwald–Hartwig), while the ketone carbonyl can be engaged in nucleophilic additions, reductive aminations, and enolate chemistry, enabling the construction of diverse and complex molecular architectures.
How should 8-Bromo-3,4-dihydronaphthalen-2(1H)-one be stored to maintain stability?
The compound should be stored in a tightly sealed container, away from light and moisture, in a cool and dry environment. These conditions are standard for halogenated organic solids and help prevent hydrolysis or decomposition. Always refer to the Aladdin Scientific SDS for specific storage temperature recommendations.
Is 8-Bromo-3,4-dihydronaphthalen-2(1H)-one suitable for Suzuki–Miyaura coupling reactions?
Yes. The aryl bromide moiety in 8-Bromo-3,4-dihydronaphthalen-2(1H)-one is well-suited for Suzuki–Miyaura cross-coupling with aryl- or alkenylboronic acids under standard palladium catalysis conditions. This reaction allows researchers to install diverse aryl and heteroaryl groups on the tetralone aromatic ring, facilitating rapid analogue synthesis and SAR exploration.
What is the significance of the bromine being at the 8-position of the tetralone scaffold?
The 8-position on the tetralone ring system is peri to the ring junction, meaning the bromine substituent is in close spatial proximity to the aliphatic ring. This regiochemistry can influence molecular conformation and may direct selectivity in subsequent reactions. From a synthetic perspective, the 8-bromo substitution provides a regiochemically defined handle for transition-metal-catalyzed functionalization, enabling access to sterically and electronically distinct analogues not easily obtained from other isomers.
References
- March, J.; Smith, M. B. March's Advanced Organic Chemistry: Reactions, Mechanisms, and Structure, 7th ed.; Wiley: Hoboken, NJ, 2013.
- Johansson Seechurn, C. C. C.; Kitching, M. O.; Colacot, T. J.; Snieckus, V. Palladium-Catalyzed Cross-Coupling: A Historical Contextual Perspective to the 2010 Nobel Prize. Angew. Chem. Int. Ed. 2012, 51, 5062–5085. doi:10.1002/anie.201107017
- Clayden, J.; Greeves, N.; Warren, S. Organic Chemistry, 2nd ed.; Oxford University Press: Oxford, 2012.
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