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Baylis-Hillman reaction morita

The Morita-Baylis-Hillman or Baylis-Hillman reaction involves the reaction between an electrophile 1, usually a carbonyl containing compound such as an aldehyde, ketone, or imine, and an activated alkene 2 in the presence of a catalyst such as an amine or phosphine to deliver an a-methylene- 3-hydroxy carbonyl or a-methylene-p-amino carbonyl adduct 3. [Pg.350]

The genesis of the Morita-Baylis-Hillman (MBH) reaction began rather inauspiciously. In 1968, Morita described the reaction between an aldehyde and acrolein nitrile as well as methyl acrylate in the presence of tricyclohexylphosphine to afford 2-(l-hydroxyethyl) acrylonitrile and 2-(l-hydroxyethyl) methyl acrylate adducts in low yields ( 20%). An example is shown below using methyl acrylate 4 and acetaldehyde 5. [Pg.350]

However, in 1972, Baylis and Hillman patented the synthesis of a-methylene-P-hydroxy carbonyl compounds between aldehydes and activated alkenes including oc,P-unsaturated aldehydes, ketones, esters, amides, and [Pg.350]

This improvement of the original Morita protocol provided a viable synthetic method, for this multi-component transformation formed a unique C-C bond and afforded functionality conducive to further derivatization in an atom economical manner albeit suffering long reaction times from days to weeks. In the early 1980s, the synthetic organic chemistry community realized the utility of this reaction and has continued into the 21 century. Thus, the reaction has been the subject of numerous reviews. Because of these recent reviews, this chapter will highlight only some literature examples of the last several years. [Pg.351]

Agganval and coworkers showed a direct correlation between the pA a of a series of quinuclidine catalysts and the reaction rate of the MBH. In the study, the reaction between 2-pyridinecarboxylaldehyde and methyl acrylate in the presence of 5 mol% of catalyst was performed with no solvent. They determined the reaction rate increased as the p a of the catalyst increased. For instance, in the presence of quinuclidine 10 (pATa = 11.3) a relative rate constant (krei) of 11.3 was reported however, when the less basic quinuclidone 22 (pA a = 6.3) was used the relative rate dropped significantly to 0.006 as shown in the table below. [Pg.353]

In addition to tertiary amines, triphenylphosphine is also an effective promoter and the use of enantiomerically pure amines or phosphines to catalyse the reaction is an interesting prospect, since the products would be synthetically useful. In addition there is also the potential for Lewis acid/Bronsted acid-catalysed asymmetric MBH reactions. While early attempts at the development of a catalytic asymmetric variant were only moderately successful, providing products with up to 50% ee, some recent progress has been made in this area and high ees have been obtained in both the MBH and aza-Baylis-Hillman reaction of a,p-carbonyls with imines. [Pg.201]

The metal-based Lewis acid derived from the camphor-derived Kgands such as (7.159) and La(OTf)3 is effective in the MBH reaction of aromatic aldehydes with a,P-unsaturated aldehydes mediated by l,4-diazabicyclo(2.2.2]octane (DABCO). The best ees (up to 95%) are obtained using sterically bulky acrylates such as a-naphthyl acrylate. More success has been obtained using Bronsted acidic organocatalysts. The partially reduced BINOL (7.160) has been used to effect enantioselective MBH reaction of aliphatic aldehydes such as (7.71) with 2-cyclohexen-l-one (7.161) mediated by triethylphosphine/ while bis(thio)ureas such as (7.163) provide up to 96% ee in the coupling of this ketone with cyclohex-anecarbaldehyde in the presence of DABCO. ° [Pg.202]

An alternate to the use of Lewis acids is the employment of amine catalysts in the MBH reaction. Hatakeyama and coworkers have used the quinidine (7.164) as a catalyst in the MBH reaction of both aromatic aldehydes such as ben-zaldehyde (7.17) and aliphatic aldehydes with the acrylate (7.165). In all cases ees are high (91-99%), but yields are moderate. This amine has also been applied to the catalysis of the aza-Bayhs-HiUman reaction of methylvinyl ketone (MVK) and methyl acrylate with N-tosylarylaldimines giving the product with high ee.  [Pg.202]

It has been shown that L-proline in combination with quinidine (7.164) and imidazole leads to some enantioselection in the MBH reaction, presumably via the formation of a iminium species by reaction of L-prohne with the a,p-unsaturated [Pg.202]

A number of BINOL-based bifunctional organocatalysts, for example (7.171-7.173), containing both Bronsted acidic and Lewis basic sites have been used to good effect in the asymmetric MBH reaction. The amine-thiourea (7.171) promotes the MBH reaction of aliphatic aldehydes with 2-cyclohexenone with ees ranging from 80 to 94% while both the (pyridinylaminomethyl)BINOL (7.172) and phosphine (7.173) catalyse the aza-Bayhs-Hilhnan reaction of simple a,p-carbonyls such as MVK and phenyl acrylate with N-tosyl arylaldmines with similar levels of enantioselectivity. [Pg.203]


The reaction of 4-95 to give a 96 4-mixture of 4-96 and 4-97 containing the central core of 4-94 was performed by heating 4-95 for 67 h at 40 °C and then adding PMe3 to induce the Morita-Baylis-Hillman reaction (Scheme 4.21). [Pg.293]

The product of the previous reaction provides a Baylis-Hillman type product via an intermolecular addition of an allenoate to an epoxide. The first example of a true Morita-Baylis-Hillman reaction of an epoxide has recently been reported <06CC2977>. Treatment of enone 34 with Me3P provides a good yield of the epoxide-opened product 35. The reaction must be carried out at low concentrations in order to avoid the generation of a variety of side products. When the terminal end of the epoxide is substituted (e.g. 34) the exo-mode of cyclization is the only product observed. When the terminal end of the epoxide is unsubstituted (e.g. 36), the endo-mode of cyclization predominates providing 37. [Pg.77]

Also known as Morita-Baylis-Hillman reaction, and occasionally known as Rauhut-Currier reaction. It is a carbon—carbon bond-forming transformation of an electron-poor alkene with a carbon electrophile. Electron-poor alkenes include acrylic esters, acrylonitriles, vinyl ketones, vinyl sulfones, and acroleins. On the other hand, carbon electrophiles may be aldehydes, a-alkoxycarbonyl ketones, aldimines, and Michael acceptors. [Pg.39]

Other successful H-bond catalysis apphcations have been introduced by Schaus and Sasai involving asymmetric Morita-Bayhs-Hilhnan (Scheme 11.13c) and aza-Morita-Baylis-Hillman reactions (Scheme 11.13d), respectively. Intriguingly, derivatized BINOL systems 33 and 34 provided optimal selectivities. [Pg.333]

The highly enantioselective Morita-Baylis-Hillman reaction of cyclohexenone with aldehydes is catalyzed by a chiral BlNOL-derived Brpnsted acid 8 in the presence of triethylphosphine as the nucleophilic promoter (Scheme 12.6). ... [Pg.361]

Fig. 11 Proposed catalytic cycle for the Morita-Baylis-Hillman reaction... Fig. 11 Proposed catalytic cycle for the Morita-Baylis-Hillman reaction...
Scheme 51 Morita-Baylis-Hillman reaction using the dual catalysts 130 and 58... Scheme 51 Morita-Baylis-Hillman reaction using the dual catalysts 130 and 58...
The most efficient catalyst system for the Morita-Baylis-Hillman reaction of methyl vinyl ketone has been reported by Miller [183, 184], Use of L-proline (58) (10 mol%) in conjunction with the A-methyl imidazole containing hexapeptide 131 (10 mol%) provided an efficient platform for the reaction of 125 with a series of aromatic aldehydes 127 (52-95% yield 45-81% ee) (Scheme 52). Importantly, it was shown that the absolute configuration of the proline catalyst was the major factor in directing the stereochemical outcome of the reaction and not the complex peptide backbone. [Pg.321]

Intramolecular versions of the Morita-Baylis-Hillman reaction have also met with success using a dual Lewis acid/Lewis base catalyst system. Miller has shown that a combination of A-methyl imidazole (132) (10 mol%) and... [Pg.321]

An interesting alternative intramolecular cyclisation was discovered by Jprgensen and co-workers [187]. Although not strictly exploiting an enamine intermediate, the transformation represents a secondary amine catalysed Morita-Baylis-Hillman reaction leading to a series of highly functionalised cyclohexene products. Reaction of the Nazarov reagent 137 with a,P-unsaturated aldehydes in the presence of the diarylprolinol ether 30 led to the cyclohexene products 138 (49-68% yield 86-96% ee) via a tandem Michael/Morita-Baylis-Hillman reaction (Scheme 54). [Pg.322]

The promoters of the so-called chalcogenide Morita-Baylis-Hillman reaction are Kataoka and co-workers who employed sulfide and TiCl for dual Lewis acid-base activation. Later, in 1996 the ability of the combination of sulfide/TBDMSOTf to promote the reaction was reported [110], Asymmetric version of the Baylis-Hillman reaction has been achieved by using chiral sulfide in place of SMe. The best ee was 94% in combination with a high yield of 88% in 5 h (Scheme 39) [ 111 ]. [Pg.368]

Scheme 37 The original Morita-Baylis-Hillman reaction [85, 86]... Scheme 37 The original Morita-Baylis-Hillman reaction [85, 86]...
P-Amino carbonyl compounds containing an a-atkyUdene group are densely functionalized materials, which are widely applied in the synthesis of medicinal reagents and natural products [265]. These products are usually prepared through the classic aza-Morita-Baylis-Hillman reaction [176, 177] of activated imines and electron-deficient alkenes catalyzed by tertiary amines or phosphines. Chen and co-workers, in 2008, identified bis-thiourea 106 as a suitable catalyst for the... [Pg.250]

Chiral BINOL (60) is a bifunctional organocatalyst in addition to the phenolic Brpnsted acid groups, it has a Lewis base unit attached via a spacer moiety.167 This particular combination holds the groups in a conformational lock, where they can doubly activate a substrate while giving a high level of stereocontrol. For this example of an aza-Morita-Baylis-Hillman reaction of an enone and an imine, yields up to 100% and ees up to 96% have been achieved. [Pg.22]

The Morita-Baylis-Hillman reaction can be accelerated by a catalytic amount of lithium bromide and l,8-diazabicyclo[5.4.0]undec-7-ene in a solvent-free medium.171... [Pg.350]

A study of the effect of the Michael acceptor configuration on the efficiency of intramolecular Morita-Baylis-Hillman reactions has been performed. Enones containing a pendant aldehyde moiety attached at the -position of the alkene group were employed as substrates and the reactions were catalysed by a phosphine. In all cases examined, with Ph3P as the catalyst, cyclization of (Z)-alkene (117) gave 2.5-8.5 times higher yield than with the E-isomer (115) under identical reaction conditions, both affording the same product (116). Steric effects are believed to be the source of this difference in reactivity.172... [Pg.350]

Using electrospray ionization mass spectrometry in both positive and negative ion modes, the on-line scanning of the Morita-Baylis-Hillman reaction in the presence of imidazolium ionic liquids has been investigated. The interception of several supramolecular species indicated that ionic liquids co-catalyse the reactions by activating the aldehyde toward nucleophilic enolate attack and by stabilizing the zwitterionic species that act as the main intermediates.175... [Pg.351]

A series of A - / - n i trobe nzenesul fony 1 imincs have been reported to undergo asymmetric aza-Morita-Baylis-Hillman reactions with methyl acrylate mediated by DABCO in the presence of chiral thiourea organocatalysts with unprecedented levels of enantioselectivity (87-99% ee), albeit only in modest yields (25 19%). Isolation of a DABCO-acrylate-imine adduct as a key intermediate, kinetic investigation, and isotopic labelling, have been employed to determine the mechanism.177... [Pg.351]

Asymmetric aza Morita-Baylis-Hillman reactions of N-sulfonylimines or N-sulfinimines with Michael accepters in the presence a Lewis base catalyst to give the corresponding chiral a-methylene-/ -amino compounds have been described [27]. [Pg.286]


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Aldol Morita-Baylis-Hillman reaction

Amines Derived from Asymmetric Aza-Morita-Baylis-Hillman Reaction

Amines Morita-Baylis-Hillman-reaction

Asymmetric aza Morita-Baylis-Hillman reaction (

Aza-Morita-Baylis-Hillman reaction

BINOL Morita-Baylis-Hillman-reaction

Baylis-Hillman

Baylis-Hillman reaction

Cinchona Morita-Baylis-Hillman reaction

DABCO Morita-Baylis-Hillman reaction

Electron Morita-Baylis-Hillman reaction

Hillman

Intramolecular Morita-Baylis-Hillman reactions

Ionic liquids Morita-Baylis-Hillman reaction

Morita

Morita Baylis Hillman

Morita-Baylis-Hillman Reaction Co-catalyzed by Ionic Liquids

Morita-Baylis-Hillman carbonates reaction

Morita-Baylis-Hillman reaction asymmetric

Morita-Baylis-Hillman reaction asymmetric reactions

Morita-Baylis-Hillman reaction catalyst

Morita-Baylis-Hillman reaction general scheme

Morita-Baylis-Hillman reaction mechanism

Morita-Baylis-Hillman reaction solvent effects

Morita-Baylis-Hillman reactions acrolein

Morita-Baylis-Hillman reactions acrylate esters

Morita-Baylis-Hillman reactions domino Michael additions

Morita-Baylis-Hillman reactions reviews

Morita-Baylis-Hillman type reaction

Organocatalysis Morita—Baylis—Hillman reaction

Phosphines Morita-Baylis-Hillman-reaction

Solvents Morita-Baylis-Hillman reaction

Systems for the Morita-Baylis-Hillman Reaction

The Baylis-Hillman Reaction and its Morita Variant

The Morita-Baylis-Hillman Reaction

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