Allenyl Chloromethyl Sulfone

[126696-78-4]  · C4H5ClO2S  · Allenyl Chloromethyl Sulfone  · (MW 152.60)

(dienophile whose Diels-Alder adducts give 1,3-dienes with base, thus allowing two-step cyclohomologation of dienes1)

Physical Data: mp 39-39.5 °C.

Solubility: sol common organic solvents.

Form Supplied in: colorless solid; not commercially available.

Preparative Methods: the reagent is prepared by addition of chloromethylsulfenyl chloride, ClCH2SCl, to Propargyl Alcohol to give S-chloromethylpropargyl sulfenate, ClCH2SOCH2C&tbond;CH, which via 2,3-sigmatropic rearrangement gives allenyl chloromethyl sulfoxide, ClCH2SOCH=C=CH2, which eventually, on oxidation, gives the title reagent (47%).1

Handling, Storage, and Precautions: potential alkylating agent; use in fume hood.


Allenyl chloromethyl sulfone is a potent dienophile whose Diels-Alder adducts give 1,3-dienes with bases via the Ramberg-Bäcklund rearrangement, thus allowing two-step cyclohomologation of dienes. Other examples of this class of reagents include chloromethyl tetradeca-1,2-dienyl sulfone [Me(CH2)10CH=C=CHSO2CH2Cl] and chloromethyl 3-methylbuta-1,2-dienyl sulfone [Me2C=C=CHSO2CH2Cl]. As shown in eq 1, allenyl chloromethyl sulfone functions as a synthetic equivalent of 1,2,3-butatriene in Diels-Alder reactions. The synthetic sequence can be used iteratively as shown in eq 2.

It is notable that chloromethylsulfenyl chloride, used in the synthesis of the title reagent (as well as other halomethylsulfenyl bromides), is a versatile reagent for the synthesis of conjugated polyenes, enones, and 1,3-oxathiole 1,1-dioxides.2

1. Block, E.; Putman, D. JACS 1990, 112, 4072.
2. Block, E.; Aslam, M.; Eswarakrishnan, V.; Gebreyes, K.; Hutchinson, J.; Iyer, R.; Lafitte, J.-A.; Wall, A. JACS 1986, 108, 4568.

Ottorino De Lucchi

Università di Venezia, Italy

Davide Fabbri

Università di Sassari, Italy

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