Preparation of Various 1,1-Dihalo-2-haloalkylcyclopropanes and 1,1,2-Trihalocyclopropanes and their Reduction to Dihalides using Tributyltin Hydride.

Conventional batch dibromocyclopropanations by reaction of bromoform and alkenes under phase-transfer conditions require strong base (50% NaOH (aq)), vigorous stirring, and often long reaction times. Using flow chemistry in a microreactor, the reactions were found to be smooth, rapid, and high-yielding under ambient conditions when 40% (w/w) NaOH was used as the base. The reaction has been tested with a representative selection of alkenes, displaying a variety of structural features.

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“…Estimated yield of 9 was 0.21 g, 57%. The spectral data were in accordance with the literature [37].…”

Section: Discussionsupporting

confidence: 71%

The Use of Flow Chemistry for Two-Phase Dibromocyclopropanation of Alkenes

Østby¹,

Stenstrøm²,

Didriksen³

2015

J Flow Chem

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“…Either addition of CBr 3 − or of :CBr 2 can be achieved specifically; 17 the similar addition of :CCl 2 has also been reported. 18 Pd-catalyzed ethoxycarbonylation of methallyl bromide (NaOEt-Na 2 PdCl 4 -[(Ph 2 P) 2 CH 2 ] 2 at rt) is also readily achieved. 19…”

Section: (2) (3) Sph Phs Phsmentioning

confidence: 99%

Methallyl Bromide

Bolton

O’Doherty

Gao

2007

Encyclopedia of Reagents for Organic Synthesis

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Br [1458-98-6] C 4 H 7 Br (MW 135.01) InChI = 1/C4H7Br/c1-4(2)3-5/h1,3H2,2H3 InChIKey = USEGQJLHQSTGHW-UHFFFAOYAS (alkylating agent attacking C, N, O, and S nucleophiles, often with enantiomeric or diastereomeric selectivity; alkyl-metal reagents provide α-(methallyl) alcohols with various carbonyl systems; provides derivatives leading to polymers and to other reagents) Alternate Name: 3-bromo-2-methylpropene. Physical Data: bp 94-95 • C; d 1.313 g cm −3 . Solubility: organic solvents; sparingly sol water. Form Supplied in: yellow to brown liquid. Purification: wash with water and aq. NaHCO 3 until washings are not acidic. Dry (MgSO 4 ) and fractionally distill. Handling, Storage, and Precautions: toxic irritant liquid; protect from light in brown glass. Use in a fume hood.

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“…This product contained one carbon atom more than the starting material, which clearly indicated that 1 had been formed, but had suffered ring-opening in a subsequent reaction. And sure enough, when the reaction was repeated with no ethanol present, cyclopropane 1 was the only product obtained, and furthermore, when 1 was treated with 50 % NaOH/TEBA/EtOH (8 equiv), ring-opening took place [3] (Scheme 1). However, it then appeared that 2 was not the only product formed; in addition, a ketal, viz.…”

Section: Introductionmentioning

confidence: 99%

From 3,3,4,4-tetraethoxybutyne to carbohydrate mimics

Sydnes

Kvernenes

Valdersnes

2005

Pure and Applied Chemistry

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3,3,4,4-Tetraethoxy-1-butyne, available in high yield in four simple steps from ethyl vinyl ether, is a highly functionalized alkyne, which appears to be a versatile starting material for the synthesis of a range of alkylated, more-or-less deoxygenated carbohydrate mimics. However, many of the reactions used to achieve extension and subsequent structural modification of the carbon chain as well as removal of the protecting groups turn out to be rather sensitive to the substituents' steric and electronic influence. As a result, the reactivity pattern that emerges is somewhat complex.

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Preparation of Various 1,1-Dihalo-2-haloalkylcyclopropanes and 1,1,2-Trihalocyclopropanes and their Reduction to Dihalides using Tributyltin Hydride.

Abstract: Fifteen members of the title compounds such as (III), (VII) or (X) are prepared by dihalocarbene addition to the corresponding alkenes, and their reduction behavior toward Bu3SnH is investigated.

Cited by 8 publications

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The Use of Flow Chemistry for Two-Phase Dibromocyclopropanation of Alkenes

The Use of Flow Chemistry for Two-Phase Dibromocyclopropanation of Alkenes

Methallyl Bromide

From 3,3,4,4-tetraethoxybutyne to carbohydrate mimics

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