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A Convenient Procedure for the Synthesis of Acetals from α‐Halo Ketones
Author(s) -
Carlson Rolf,
Gautun Hanna,
Westerlund Andreas
Publication year - 2002
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/1615-4169(200201)344:1<57::aid-adsc57>3.0.co;2-0
Subject(s) - chemistry , halo , organic chemistry , combinatorial chemistry , computational chemistry , galaxy , quantum mechanics , physics
A study for determining the scope and limitations of a procedure for synthesising ethylene acetals from haloketones is presented. The method uses 1,2‐bis(trimethylsilyloxy)ethane, BTSE, as reagent and Nafion ® ‐TMS as catalyst. Two procedures have been tested: (A) stoichiometric amounts of the haloketone and BTSE and a catalytic amount of Nafion ® ‐TMS were heated to reflux in chloroform solution, and (B) stoichiometric amounts of the reactants and a catalytic amount of Nafion ® ‐TMS were heated to 90–100 °C in the absence of solvent. The following ketones have been tested: 2‐bromo‐1‐phenyl‐1‐ethanone, 2‐bromo‐cyclopentenone, 3‐bromo‐3‐methyl‐2‐butanone, 3‐chloro‐3‐methyl‐2‐butanone, 1‐bromo‐3,3‐dimethyl‐2‐butanone, 1‐chloro‐3,3‐dimethyl‐2‐butanone, 2‐bromocyclohexanone, 2‐chloro‐1‐cyclohexyl‐1‐ethanone, 1,1‐dibromo‐3,3‐dimethyl‐2‐butanone, 1,3‐dibromo‐3‐methyl‐2‐butanone, 1,3‐dibromo‐2‐butanone, 1,3‐dibromo‐2‐propanone, 2‐chloro‐1‐phenyl‐1‐ethanone, and endo ‐2‐bromocamphor. Yields were in the range 57–100% with the exceptions of endo ‐2‐bromocamphor which afforded <10% yield and the dibromoketones 1,1‐dibromo‐3,3‐dimethyl‐2‐butanone and 1,3‐dibromo‐3‐methyl‐2‐butanone for which the method failed. Factors determining the scope and limitations are briefly discussed. Full experimental details and spectroscopic data of the acetals are given.