- Contrasting chemoselectivities in the ultrasound and microwave assisted bromination reactions of substituted alkylaromatics with N-bromosuccinimide
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Ultrasound and microwave assisted bromination reactions of various alkylaryls with N-bromosuccinimide, either neat or in water, shows diverse chemoselectivity. Thus, ring substitution occurs in water with ultrasound, whereas with microwaves both side-chain α-bromination and ring substitution occur. With neat reactants, side-chain α-bromination predominates for microwave assisted reactions. In the presence of water the chemoselectivity with microwave-promoted bromination is similar to that observed using classical methods.
- Heropoulos, Georgios A.,Cravotto, Giancarlo,Screttas, Constantinos G.,Steele, Barry R.
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- Palladium-Catalyzed Alkylation with Alkyl Halides by C(sp3)?H Activation
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Utilizing halogens as traceless directing goups represents an attractive strategy for C?H functionalization. A two C?H alkylation system, initiated by the oxidative addition of organohalides to Pd0, has been developed. The first reaction involves an intermolecular alkylation of palladacycles to form C(sp3)?C(sp2) bonds followed by C(sp2)?H activation/cyclization to deliver alkylated benzocyclobutenes as the final products. In the second reaction, two C?C bonds are formed by the reaction of palladacycles with CH2Br2, and provides a facile and efficient method for the synthesis of indanes. The alkylated benzocyclobutene products can be transformed into tricyclic hyrocarbons, and the indane derivatives are essential structural motifs in bioactive and odorant molecules.
- Wu, Zhuo,Ma, Ding,Zhou, Bo,Ji, Xiaoming,Ma, Xiaotian,Wang, Xiaoling,Zhang, Yanghui
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supporting information
p. 12288 - 12291
(2017/09/06)
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- The Synthesis and Structure of 3,4-Di-t-butylbenzoic Acid
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3,4-Di-t-butylbenzoic acid (1) was synthesized by a seven-step sequence from 4-t-butylbenzoic acid, and its structure was determined by X-ray diffraction and refined to a residual of 0.065 for 1403 independent observed reflections.The crystals are triclinic, P1, a 6.080(1), b 8.777(1), c 13.912(3) Angstroem, α 80.76(2), β 80.84(2), γ 75.62(2)deg.It is the only example of a simple ortho-di-t-butylbenzene whose structure has been determined.The benzene ring experiences some out-of-plane distortion but, in general, strain is relieved by in-plane bond stretching and angular distortions.
- Hambley, Trevor W.,Sternhell, Sever,Tansey, Charles W.
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p. 807 - 814
(2007/10/02)
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