Base-induced cyclization of .alpha.-chloro .beta.,.gamma.-unsaturated ketones : facile synthesis of tri- and tetrasubstituted 2-cyclopenten-1-ones
摘要:
Base-induced cyclization of fully substituted alpha-chloro beta,gamma-unsaturated ketones results in substituted cyclopentenones. Potassium tert-butoxide, lithium diisopropylamide, sodium hydroxide, and ammonium hydroxide can be used as the base for this process. In the case of ammonium hydroxide, it is proposed that initial formation of an enamine is followed by an intramolecular S(N)2' reaction of the enamine carbon. For all other bases, the reaction most likely proceeds through a ketone enolate. Application of this novel cyclization has been extended to the synthesis of several 2,3-disubstituted, 2,3,5-trisubstituted, and 2,3,5-tetrasubstituted 2-cyclopenten-1-ones.
Base-induced cyclization of .alpha.-chloro .beta.,.gamma.-unsaturated ketones : facile synthesis of tri- and tetrasubstituted 2-cyclopenten-1-ones
摘要:
Base-induced cyclization of fully substituted alpha-chloro beta,gamma-unsaturated ketones results in substituted cyclopentenones. Potassium tert-butoxide, lithium diisopropylamide, sodium hydroxide, and ammonium hydroxide can be used as the base for this process. In the case of ammonium hydroxide, it is proposed that initial formation of an enamine is followed by an intramolecular S(N)2' reaction of the enamine carbon. For all other bases, the reaction most likely proceeds through a ketone enolate. Application of this novel cyclization has been extended to the synthesis of several 2,3-disubstituted, 2,3,5-trisubstituted, and 2,3,5-tetrasubstituted 2-cyclopenten-1-ones.
MATHEW, JACOB, J. ORG. CHEM., 56,(1991) N, C. 713-716
作者:MATHEW, JACOB
DOI:——
日期:——
Base-induced cyclization of .alpha.-chloro .beta.,.gamma.-unsaturated ketones : facile synthesis of tri- and tetrasubstituted 2-cyclopenten-1-ones
作者:Jacob Mathew
DOI:10.1021/jo00002a042
日期:1991.1
Base-induced cyclization of fully substituted alpha-chloro beta,gamma-unsaturated ketones results in substituted cyclopentenones. Potassium tert-butoxide, lithium diisopropylamide, sodium hydroxide, and ammonium hydroxide can be used as the base for this process. In the case of ammonium hydroxide, it is proposed that initial formation of an enamine is followed by an intramolecular S(N)2' reaction of the enamine carbon. For all other bases, the reaction most likely proceeds through a ketone enolate. Application of this novel cyclization has been extended to the synthesis of several 2,3-disubstituted, 2,3,5-trisubstituted, and 2,3,5-tetrasubstituted 2-cyclopenten-1-ones.