When ethyl is infinitely different from methyl: double addition of lithiated dithianes to aromatic carboxylates revisited.
Addition of lithiated alkyl dithianes to benzoyl chloride or methyl benzoate does not produce the expected product of double addition, alpha,alpha-bis(alkyldithianyl) benzyl alcohol, for alkyls larger than methyl. Instead, the first step intermediate, i.e. 2-benzoylated dithiane, undergoes an electron-transfer reduction by the second molecule of the dithianyl anion. This reduction is followed by the ring-opening mesolytic fragmentation of the dithiane ring in the ketyl anion radical and subsequent radical recombination yielding acetophenone-tethered thioortho esters 4, alpha-[3-(2-alkyl-1,3-dithiane-2-ylthio)propylthio]-alpha-alkyl-acetophenones. It appears that the Corey-Seebach bisaddition of lithiated dithianes to methyl benzoate is an exception rather than the rule in the alkyl dithiane series.
Valiulin
Roman A
RA
Department of Chemistry and Biochemistry, University of Denver, Denver, Colorado 80208-2436, USA.
Kottani
Rudresha
R
Kutateladze
Andrei G
AG
D002264:Carboxylic Acids / Q000737:chemistry*; D006841:Hydrocarbons, Aromatic / Q000737:chemistry*; D008094:Lithium / Q000737:chemistry*; D015394:Molecular Structure; D011807:Quinolizines / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D013457:Sulfur Compounds / Q000737:chemistry*
D002264:Carboxylic Acids; D006841:Hydrocarbons, Aromatic; D011807:Quinolizines; D013438:Sulfhydryl Compounds; D013457:Sulfur Compounds; C438055:dithiane; D008094:Lithium