Boord olefin synthesis

The Boord olefin synthesis is an organic reaction forming alkenes from ethers carrying a halogen atom 2 carbons removed from the oxygen atom (β-halo-ethers) using a metal such as magnesium or zinc. The reaction, discovered by Cecil E. Boord in 1930 ^[1] is a classic named reaction with high yields and broad scope.^[2]

The reaction type is an elimination reaction with magnesium forming an intermediate Grignard reagent. The alkoxy group is a poor leaving group and therefore an E1cB elimination reaction mechanism is proposed.^[2] The original publication describes the organic synthesis of the compound isoheptene in several steps.

In a 1931 publication ^[3] the scope is extended to 1,4-dienes with magnesium replaced by zinc (see also: Barbier reaction). In the first part of the reaction the allyl Grignard acts as a nucleophile in nucleophilic aliphatic substitution.

References

^ The synthesis of beta-bromo-alkyl ethers and their use in further synthesis Lloyd C. Swallen and Cecil E. Boord J. Am. Chem. Soc.; 1930; 52(2) pp 651 - 660; doi:10.1021/ja01365a033
^ ^a ^b Advanced Organic Chemistry, 4th Edition, Jerry March, 1992.
^ Nuclear syntheses in the olefin series II. 1,4-diolefins Bernard H. Shoemaker and Cecil E. Boord J. Am. Chem. Soc.; 1931; 53(4) pp 1505 - 1512; doi:10.1021/ja01355a049

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[1] The synthesis of beta-bromo-alkyl ethers and their use in further synthesis Lloyd C. Swallen and Cecil E. Boord J. Am. Chem. Soc.; 1930; 52(2) pp 651 - 660; doi:10.1021/ja01365a033

[March-2] Advanced Organic Chemistry, 4th Edition, Jerry March, 1992.

[3] Nuclear syntheses in the olefin series II. 1,4-diolefins Bernard H. Shoemaker and Cecil E. Boord J. Am. Chem. Soc.; 1931; 53(4) pp 1505 - 1512; doi:10.1021/ja01355a049

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v t e Alkenes
Alkenes	Ethene (C₂H₄) Propene (C₃H₆) Butene (C₄H₈) Pentene (C₅H₁₀) Hexene (C₆H₁₂) Heptene (C₇H₁₄) Octene (C₈H₁₆) Nonene (C₉H₁₈) Decene (C₁₀H₂₀)
Preparations	Dehydrohalogenation from haloalkane Dehydration reaction from alcohol Semihydrogenation from alkyne Bamford–Stevens reaction Barton–Kellogg reaction Boord olefin synthesis Chugaev elimination Cope reaction Corey–Winter olefin synthesis Grieco elimination Hofmann elimination Horner–Wadsworth–Emmons reaction Hydrazone iodination Julia olefination Kauffmann olefination McMurry reaction Peterson olefination Ramberg–Bäcklund reaction Shapiro reaction Takai olefination Wittig reaction Olefin metathesis Ene reaction Cope rearrangement
Reactions	Hydrogenation Halogenation Hydration Electrophilic addition Oxymercuration reaction Hydroboration Cyclopropanation Epoxidation Dihydroxylation Ozonolysis Hydrohalogenation Polymerization Diels–Alder reaction Wacker process Dehydrogenation Ene reaction Friedel-Crafts Alkylation