122277-40-1Relevant academic research and scientific papers
Formation of carbocycles by intramolecular conjugate displacement: Scopeand mechanistic insights
Wang, Lihong,Prabhudas, Bodhuri,Clive, Derrick L. J.
supporting information; experimental part, p. 6003 - 6012 (2009/09/25)
A detailed study has been made of a method of ring closure categorized as an all-carbon intramolecular conjugate displacement (ICD). This reaction involves intramolecular addition of a carbanion, which is stabilized by at least one electron-withdrawing group, to a Michael acceptor which has a leaving group in an allylic position. The process formally resembles a combination of Michael addition and S N2' displacement. The overall result is formation of a ring with loss of the allylic leaving group and shift of the original double bond to a new location spanning the positions of the electron-withdrawing substituent of the Michael acceptor subunit and the original allylic leaving group. The starting materials are easily prepared by a selenium-based version of the Morita-Baylis-Hillman reaction. The cyclizations are transition metal free and occur under mild conditions, using DBU or Cs 2CO 3 inMeCN or THF. Acetate is a suitable leaving group and the electron-withd rawing substituent of the Michael acceptor unit can be CO 2R,SO 2Ph, or CN. Six- and seven-membered rings are formed effi ciently, and complex structures, such as those resembling the core of CP-225,917, are easily assembled. The products of these ICD reactions are themselves classical Michael acceptors. A range of mechanisms probably operates, depending on the structure of the starting material and the reaction conditions, but conclusive evidence for a stepwise mechanism was obtained in a suitably biased case, while other observations are compatible with a concerted process or a stepwise path involving a short-lived carbanion that evades capture by a proton source.
Intramolecular conjugate displacement: A general route to hexahydroquinolizines, hexahydroindolizines, and related [m,n,0]-bicyclic structures with nitrogen at a bridgehead
Clive, Derrick L. J.,Li, Zhiyong,Yu, Maolin
, p. 5608 - 5617 (2008/02/09)
(Chemical Equation Presented) N-Protected amino aldehydes can be converted into allylic alcohols by the classical Morita-Baylis-Hillman reaction (cf. 2 → 3) or by condensation with selenium-stabilized carbanions, followed by oxidation (cf. 2 → 8 → 3). The
Synthesis of homoallylic sulphides and selenides by Lewis acid mediated displacement reactions of sulphones
Simpkins, Nigel S.
, p. 323 - 332 (2007/10/02)
A number of α-seleno- and α-thio-substituted sulphones have been prepared, and subsequently reacted with allyltrimethylsilane, using EtAlCl2 as Lewis acid, to give homoallylic selenides or sulphides respectively. Some unsaturated substrates und
SYNTHESIS OF ALLYLIC SULPHIDES AND SELENIDES BY LEWIS ACID MEDIATED DISPLACEMENT REACTIONS OF SULPHONES
Simpkins, Nigel S.
, p. 6787 - 6790 (2007/10/02)
Allylic sulphides or selenides are produced by reaction of appropriate α-sulphonyl sulphides or selenides with allyltrimethylsilane in the presence of EtAlCl2.
