Morita conditions

Thiourea catalyst 139 was also screened in the asymmetric Friedel-Crafts reaction between 2-naphthol trans-nitrostyrene (73% yield 0% ee 18 h in toluene at -20 °C and 10 mol%) [277], in the asymmetric aza-Michael reaction of O-benzyl-hydroxylamine to chalcone (72% conv. 19% ee 72 h in toluene at 20 °C and 20mol% catalyst loading) [293], and in the asymmetric Morita-BayUs-HiUman [176, 177] reaction between cyclohexenecarbaldehyde and 2-cyclohexene-l-one (20% yield 31% ee 46 h at rt and 20mol% DABCO and 139) [310]. In aU these transformations, thiourea 139 proved to be not competitive to the organocatalysts probed for these transformations under identical screening conditions and thus was not employed in the optimized protocols. 

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... 

Methylimidazole 3-A-oxide (49) catalyses the Morita-Baylis-Hillman reaction at room temperature under solvent-free conditions addition to the enone reactant to give a zwitterionic enolate (50) is proposed, followed by reaction with aldehyde.177... 

A A /V /V -Tetramethylelhylcncdiaminc (TMEDA) as catalyst of the Morita-Baylis-Hillman reaction has been found to be more efficient than DABCO in aqueous media.146 1-Methylimidazole 3-/V-oxide promotes the Morita-Baylis-Hillman reaction of various activated aldehydes with ,/i-unsaturated ketones and esters CH2= CHCOR (R = Me, OMe) in solvent-free systems.147 In another study, the Morita-Baylis-Hillman reaction has been successfully performed under aqueous acidic conditions at pH 1, using a range of substrates and tertiary amines as catalysts.148... 

Fig. 5.13. Gas chromatogram of silylated phenolic acids. Peaks 1 = p-hydroxybenzoic 2 = vanillic 3 = syringic 4 = p-coumaric 5 = ferulic 6 = sinapic acid 7 = n-docosane. Conditions glass column, 9 ft. X 1/4 in. O.D., 3% UCW-98 on Chromosorb W HP<100-120 mesh) nitrogen flow-rate, 40 ml/ min temperature programme, 6°C/min from 100°C. (Reproduced from J. Chromatogr., 71 (1972) 149, by courtesy of H. Morita.)...

In 2007, Jorgensen and coworkers also reported the anti-Michael reaction of the cyclic P-ketoesters 53 with the sulfone group-substituted acrylonitrile 54 under PTC conditions (52 (6mol%), CHC13, aq Cs2C03 or K3P04) [15]. As depicted in Scheme 9.18, the sulfone group of the acceptor directed the nucleophile and then is removed to afford the anti-Michael (a-addition Morita-Baylis-Hillman-like) adducts 55 in variable yields (42-90%) and ee values (60-94% ee) (Scheme 9.18). 

Morita, T., Okamoto, Y., and Sakurai, H., A mild and facile synthesis of alkyl- and arylphosphonyl dichlorides under neutral conditions. Reaction of Z)ri(trimethylsilyl) phosphonates with PClj, Chem. Lett., 435, 1980. 

Each 10 year-old tree of Morita navel orange was grown in a hexagonal concrete pot in the field at Shizuoka Prefectural Experiment Station, Shimizu, Shizuoka. Until the previous summer, trees were grown under one of the following three conditions -... 

M30. Morita, J., and Kashimura, N., Involvement of monosaccharide autoxidation in DNA glycation under physiological conditions. In The Maillard Reaction Advances in Life Sciences (P. A. Finot, ed.), pp. 505-510. Birkhauser Verlag, Basel, 1990. 

S-1 remained unaltered (Morita et al, 1991). Similar conditions were used for the exchange of recombinant LC20 into smooth muscle myosin (Kamisoyama et al., 1994). 

At the same time as new applications of ionic liquids are discovered on almost a daily basis, limitations of these reaction media are also uncovered. While studying the Morita-Baylis-Hillman reaction in ionic liquids, Aggarwal observed that [bmim][Cl] was deprotonated by the weak base present in the reaction mixture, leading, after reaction with benzaldehyde, to salt 111 (Scheme 49). Deprotonation of imidazolium salts with strong bases (KCyBu or NaH) is well known, providing, for example, an easy route to Pd-carbene complexes (Section 2.3.5.1). However, this observation limits the use of imidazolium-based ionic liquids even in weakly basic conditions, where they can react with electrophiles. It also explains previous works reporting low yields for reactions performed in these conditions, such as the Horner-Wadsworth-Emmons reaction in [emimlCPFe] or [emim][BF4]. ... 

The addition of electrophilic alkenes to aldehydes in the presence of strong bases occurs under SCCO2 conditions (Morita-Baylis-Hillman reaction (Scheme 29). The reaction proceeds faster in SCCO2 than in organic solvents. At relatively low CO2 pressures ( 80-100 bar), further intermolecular dehydration (dimerization) of the product leads to ethers 18. Unsymmetrical ethers are synthesized using another alcohol in the etherification step. 

The practical value of DMP as a reagent has been extended to various other synthetically useful oxidative transformations, such as the dehydration of primary alcohols under extraordinarily mild conditions [1276], synthesis of various polycyclic heterocycles via the oxidative cascade cyclization of anilides with pendant double bonds [1277], one-pot oxidative allylation of Morita-Baylis-Hillman adducts with allyltrimethylsilane promoted by DMP/Bp3-OEt2 [1278], synthesis of 2-amino-l,4-benzoquinone-4-phenylimides from anilines via DMP oxidation [1279], a-tosyloxylation of ketones using DMP and p-toluenesulfonic acid [1280] and the DMP-mediated oxidative aromatization of 1,3,5-trisubstitutedpyrazolines [1281]. 

Fujii T, Lin F, Morita Y. Fatigue behavior of plain woven glass-fabric laminates under tension/torsion combined loading (Effect of shear stress and cyclic condition on fatigue failure). Nippon Kikai Gakkai Ronbunshu, A Hen/Trans Jpn Soc Mech Eng Part A 1994 60 650—7 [in Japanese]. 

Significant rate enhancement of the Morita-Baylis-Hillman reaction through solid-state milling has been noted by Mack et al. (Scheme 2.44). [39], In such conditions, Baylis-HiUman products 130 were obtained in up to >98% yield in as little as 0.5 h by solvent-free reaction of p-nitrobenzaldehyde 129 and methyl acrylate 128. Various bases were tested and l,4-diazabicyclo[2.2.2]octane (DABCO) showed the best performance (Table 2.41). Other p-substimted aromatic aldehydes reacted with methyl acrylate much slower, within 9 5 h and lower yields (28-97%) were obtained. This represents one of the fastest methods of Bayhs-Hilhnan reactions under neat conditions. One of the main drawbacks of this reaction carried out in classical conditions is its slow rate, which has been shown typically to take days to weeks to produce adequate product yields. 

Some other very important events in the historic development of asymmetric organocatalysis appeared between 1980 and the late 1990s, such as the development of the enantioselective alkylation of enolates using cinchona-alkaloid-based quaternary ammonium salts under phase-transfer conditions or the use of chiral Bronsted acids by Inoue or Jacobsen for the asymmetric hydro-cyanation of aldehydes and imines respectively. These initial reports acted as the launching point for a very rich chemistry that was extensively developed in the following years, such as the enantioselective catalysis by H-bonding activation or the asymmetric phase-transfer catalysis. The same would apply to the development of enantioselective versions of the Morita-Baylis-Hillman reaction,to the use of polyamino acids for the epoxidation of enones, also known as the Julia epoxidation or to the chemistry by Denmark in the phosphor-amide-catalyzed aldol reaction. ... 

Morita K, Kim BN, Yoshida H, Hiraga K (2009) Spark-plasma-sintering condition optimization for producing transparent MgAl204 spinel polycrystal. J Am Caam Soc 92 1208-1216... 

If these conditions hold then we have the following lemma, proven by Morita... 

Morita et al. (26) pointed out that the extraction rate parameters calculated by many workers under different hydrogen pressures on the basis of isothermal and isobaric conditions may be erroneous. In batch experiments, the hydrogen absorption rate showed curious behavior. They carried out experiments at temperatures up to 713 K, residence time from 120 secs to 7200 secs and initial hydrogen pressures from 5 MPa to 11 MPa and observed that the absorption of hydrogen was initiated at about 573 K. 

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