3- acryloyl-2-oxazolidinone

The complexation procedure included addition of an equimolar amount of R,R-DBFOX/Ph to a suspension of a metal salt in dichloromethane. A clear solution resulted after stirring for a few hours at room temperature, indicating that formation of the complex was complete. The resulting solution containing the catalyst complex was used to promote asymmetric Diels-Alder reactions between cyclopen-tadiene and 3-acryloyl-2-oxazolidinone. Both the catalytic activity of the catalysts and levels of chirality induction were evaluated on the basis of the enantio-selectivities observed for the endo cycloadduct. 

Although the aqua nickel(II) complex A was confirmed to be the active catalyst in the Diels-Alder reaction, no information was available about the structure of complex catalyst in solution because of the paramagnetic character of the nickel(II) ion. Either isolation or characterization of the substrate complex, formed by the further complexation of 3-acryloyl-2-oxazolidinone on to the l ,J -DBFOX/ Ph-Ni(C104)2 complex catalyst, was unsuccessful. One possible solution to this problem could be the NMR study by use of the J ,J -DBFOX/Ph-zinc(II) complex (G and H, Scheme 7.9) [57]. 

High levels of asymmetric induction (97-74% ee) along with high diastereoselectivity (>99 1-64 36) were reported for asymmetric 1,3-dipolar cycloaddition reactions of fused azomethine imines 315 and 3-acryloyl-2-oxazolidinone 709 leading to 711 using a chiral BINIM-Ni(n) complex 710 as a chiral Lewis acid catalyst (Equation 100) <20070L97>. 

High diastereomeric ratios were observed in the 1,3-DC of various nitrile oxides to the chiral acryloylhydrazide 38. For example benzonitrile oxide afforded the isoxazoline 40 in 98% de <00TL1453>. The levels of facial selectivity obtained in the same 1,3-DC with the chiral 3-acryloyl-2-oxazolidinone 39 was very low (dr 43 57), but in the presence of MgBr2 (1 equiv) the reaction proceeded with high diastereoselectivity to give preferentially the isoxazolidine 41 in 92% de <00TL3131>. 

Diels-Alder reactions of (Z)-A -substituted-4-methylene-5-propylidene-2-oxazoli-dinone dienes with methyl vinyl ketone, methyl propiolate, and captodative alkenes yield the highest regio- and stereo-selectivities in mixtures of H20 and MeOH or under BF3.Et20 catalysis.198 The asymmetric Diels-Alder reaction of cyclopentadiene and 3-acryloyl-2-oxazolidinone is catalysed by a new Cu(II) catalyst containing a chiral sterically congested roofed (2-diphenylphosphino)phenylthiazoline ligand (169).199... 

Suga and coworkers reported utility of a Yb(OTf)3-PyBOX complex in 1,3-dipolar cycloaddition reactions of carbonyl ylide generated using Rh2(OAc)4 [71, 72]. As shown in Scheme 13.26, the Yb(OTf)3/Ph-PyBOX complex promoted the reaction of 2-benzopyryrium-4-olate with 3-acryloyl-2-oxazolidinone in endojexo = 12 88,... 

In the presence of a catalyst consisting of Ni(C104)2-6H20 and the chiral binaphthyldiimine (BDSflM) ligand 141, the first chiral Lewis acid-catalyzed dipole-HOMO/dipolarophile-LUMO-controlled asymmetric 1,3-DC reactions of azomethine imines 138 and 3-acryloyl-2-oxazolidinone 139 were achieved by Suga and... 

Suga, H., Funyu, A., Kakehi, A. (2007). Highly enantioselective and diastereoselective 1,3-dipolar cycloaddition reactions between azomethine imines and 3-acryloyl-2-oxazolidinone catalyzed by binaphthyldiimine-Ni(II) Complexes. Organic Letters, 9, 97-100. 

Furthermore, Suga et al. demonstrated that binaphthyldiimide-Ni(II) complex works as a highly effective chiral Lewis acid catalyst for the VMM reaction of 3-acryloyl-2-oxazolidinone 132b with 109f (Scheme 57). [98] Likewise, Feng examined the effect of chiral N,N -dioxide ligands in the VMM reaction of chalcone derivatives [99]. 

TABLE 7.1 Asymmetric Cycloaddition Reactions of Azomethine Imines with 3-Acryloyl-2-oxazolidinone ... 

Recently, Suga et al. demonstrated that BINIM-Ni(II) catalysts are also effective in affording high levels of asymmetric induction (up to 97% ee) for 1,3-dipolar cycloaddition reactions between ethyl diazoacetate and 3-acryloyl-2-oxa-zolidinone or 2- (2-alkenoyl)-3-pyrazolidinone derivatives in the selective formation of 2-pyrazolines having a methine carbon substituted to the coordination auxiliary groups [27]. The cycloadditions of 3-acryloyl-2-oxazolidinone and its... 

SCHEME 7.14 Asymmetric cycloaddition reactions between ethyl diazoacetate and 3-acryloyl-2-oxazolidinone, its 5,5-dimethyl derivative, or 2-acryloyl-l-benzyl-5,5-dimethyl-3-pyrazolidinone. 

SCHEME 7.27 Asymmetric cycloaddition reactions of 2-benzopyrylium-4-olate with 3-acryloyl-2-oxazolidinone catalyzed by PyBOX-Ph-Yb(IH) complex. 

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