Intramolecular Stetter cyclisation of Morita–Baylis–Hillman adducts: a versatile approach towards bicycloenediones

Wasnaire, Pierre; Merode, Thierry de; Markó, István E.

doi:10.1039/b710492h

Cited by 20 publications

(11 citation statements)

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“…Marko and co-workers , have developed an interesting synthesis of bicyclic enedione, hydrindanones, and decalone derivatives from the Baylis−Hillman adducts obtained from cycloalkenones and terminal alkenals, following the reaction sequence shown in Schemes and .…”

Section: Applications Of Baylis−hillman Adducts and Their Derivatives...mentioning

confidence: 99%

Recent Contributions from the Baylis−Hillman Reaction to Organic Chemistry

2010

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Section: Applications Of Baylis−hillman Adducts and Their Derivatives...mentioning

confidence: 99%

Recent Contributions from the Baylis−Hillman Reaction to Organic Chemistry

2010

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“…We treated aldehyde 29e with the thiazolium salt 45 in the presence of Et 3 N and obtained a 2:3 mixture of the expected ICD product 29f and the simple Michael addition product 29f′ . Formation of 29f is related to a known intramolecular Stetter reaction, while 29f′ was the only case where an acetate leaving group is retained, and we discuss below the mechanistic implications of this outcome.…”

Section: Introductionmentioning

confidence: 99%

Formation of Carbocycles by Intramolecular Conjugate Displacement: Scope and Mechanistic Insights

2009

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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(N)2' 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(2)CO(3) in MeCN or THF. Acetate is a suitable leaving group and the electron-withdrawing substituent of the Michael acceptor unit can be CO(2)R, SO(2)Ph, or CN. Six- and seven-membered rings are formed efficiently, 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.

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“…Markó and co-workers utilized the Stetter reaction in the synthesis of bicycloenediones, proceeding in moderate yields using stoichiometric thiazolium pre-catalyst 74 (Equation 14) [90]. Morita-Baylis-Hillman adducts 139 were formed in three steps from commercially available starting materials 4-pentenal 138 and the corresponding cyclic enones 137 .…”

Section: Stetter Reactionmentioning

confidence: 99%