Synthesis of Unsymmetrically and Highly Substituted Thiophenes Utilizing Regioselective Ring-expansion of gem-Dichlorocyclopropyl Ketones with Lawesson's Reagent
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Ring-expansion of aryl <I>gem</I>-dichlorocyclopropyl ketones <B>1</B> using Lawesson's reagent afforded unsymmetrically and highly substituted 5-chloro and 3-chlorothiophenes <B>2</B> and <B>3</B> with excellent regioselectivity. The Suzuki–Miyaura coupling of <B>2</B> and <B>3</B> with PhB(OH)<SUB>2</SUB> was successfully performed to give 2-aryl-3-methyl-5-phenylthiophenes <B>4</B> and 2-aryl-3-methyl-4,5-diphenylthiophenes <B>5</B>, respectively.
- Chemistry Letters
Chemistry Letters 36(1), 62-63, 2007-01-05
The Chemical Society of Japan