Asymmetric Diels-Alder cycloaddition reactions with chiral .alpha.,.beta.-unsaturated N-acyloxazolidinones

Evans, David A.; Chapman, Kevin T.; Bisaha, John J.

doi:10.1021/ja00212a037

Cited by 685 publications

(349 citation statements)

References 1 publication

(1 reference statement)

Supporting

Mentioning

332

Contrasting

Unclassified

Order By: Relevance

“…In a study of the Diels-Alder reaction of 2-methoxy-l,3-butadiene with 4-benzyl-3-crotonyl-2-oxazolidinone of known absolute stereochemistry [4S (Myers & Kukkola, 1991)], the conditions that we developed for optimum diastereoselectivity and yield deviated substantially from reported literature procedures for analogous substrates (Evans, Chapman & Bisaha, 1988). Accordingly, the relative stereochemistry of the cycloadduct (1) which we synthesized could not be confidently assigned by analogy with earlier examples.…”

mentioning

confidence: 80%

A chiral N-crontonyloxazolidinone Diels-Alder adduct

Marsh¹,

Schaefer²,

Kukkola³

et al. 1992

Acta Crystallogr C

View full text Add to dashboard Cite

mentioning

confidence: 80%

A chiral N-crontonyloxazolidinone Diels-Alder adduct

Marsh¹,

Schaefer²,

Kukkola³

et al. 1992

Acta Crystallogr C

View full text Add to dashboard Cite

“…The results obtained are explained by the formation of a dienophile-TiC14 chelate complex, which amplifies diastereofacial discrimination (4). Also several Nacryloyl and N-crotonyl compounds, such as the N-acyloxazolidones (5) and the N-acylsultams (6) derived from camphor, have been used as chiral dienophiles.…”

mentioning

confidence: 99%

Natural amino acids as chiral auxiliaries in asymmetric Diels–Alder reactions

Bueno¹,

Cativiela²,

Mayoral³

et al. 1988

Can. J. Chem.

View full text Add to dashboard Cite

M. ANDRBS. Can. J. Chem. 66, 2826Chem. 66, (1988. To test whether a-amino acids can be efficient chiral auxiliaries in asymmetric Diels-Alder reactions, the chiral dienophile N-acryloyl-L-phenylalanine methyl ester was made to react with cyclopentadiene. Diastereofacial selectivity is to a great extent dependent on the Lewis acid used to promote the reaction; whereas moderate excesses of the (1 R, 2R)-cycloadduct were achieved with AlC13, the reaction did not show diastereofacial selectivity when titanium catalysts were used. Moreover, with T~('PI-(I)4 a transesterification reaction, which leads to the isopropyl ester and competes with the Diels-Alder reaction, was observed. In spite of the structural similarity of this dienophile to the acrylate of (S)-ethyl lactate, it behaved very differently in the titanium-catalyzed reactions.MARIA P. BUENO, CARLOS CATIVIELA, JOSB A. MAYORAL, ALBERTO AVENOZA, PAULA CHARRO, MIGUEL A. ROY et Josg M. ANDRBS. Can. J. Chem. 66,2826Chem. 66, (1988.Afin de dCterminer si les acides a-aminCs peuvent Ctre des auxiliaires chiraux efficaces dans des reactions de Diels-Alder asymCtriques, on a fait rCagir le cyclopentadikne avec le diknophile chiral suivant : l'ester mCthylique de la N-acryloyl-Lphenylalanine. La sClectivitC diastCrCofaciale dCpend beaucoup de l'acide de Lewis utilisC pour promouvoir la rCaction; alors que le AlC13 nous permet d'obtenir de legers excks du cycloadduit-(lR, 2R), on n'a pas detect6 de sClectivitC diastCrCofaciale lorsqu'on a utilisC des catalyseurs de titane. De plus, avec le Ti(i-Pr0)4, on a observC une rCaction de transestCrification qui entre en competition avec la rCaction de Diels-Alder et qui conduit i la formation de l'ester isopropylique. D'un point de vue structural, ce diknophile ressemble beaucoup i l'acrylate du (S)-lactate d'Cthyle; malgrC ces ressemblances, les deux se comportent trks differemment au cours de reactions catalysees par le titane.[Traduit par la revue]High levels of diastereofacial selectivity have been achieved = 1 :6 (Scheme 1). The results of the reactions were determined in asymmetric Diels-Alder additions of prochiral 1,3-dienes to dienophiles with a removable, chiral-directing auxiliary (1). However, it is interesting to test whether chiral reagents, both enantiomers of which are inexpensive and easily available, can be efficient chiral auxiliaries in this kind of reaction. In this context, reactions of acrylates (2) and fumarates (3) of several derivatives of chiral hydroxy acids with cyclopentadiene are reported to proceed with good selectivity, mainly when TiC14 is used to promote the reaction. The results obtained are explained by the formation of a dienophile-TiC14 chelate complex, which amplifies diastereofacial discrimination (4). Also several Nacryloyl and N-crotonyl compounds, such as the N-acyloxazolidones (5) and the N-acylsultams (6) derived from camphor, have been used as chiral dienophiles.In spite of their availability, inexpensive natural a-amino acids, which have been used in a lot of asymmetric reactio...

show abstract

“…Kirst et al (3) suggested that the biosynthesis of spinosyn A may involve a transannular Diels-Alder (TDA) (13) reaction of a macrocyclic pentaene to form the C(4)OC (12) and C(7)OC (11) bonds (see 4 3 3; Scheme 1). Kirst also suggested that a transannular cyclization of a 1,3-dicarbonyl nucleophile may generate the C(3)OC (14) bond (3). Alternatively, we speculated that the C(3)OC (14) bond may be formed by a vinylogous Morita-Baylis-Hillman (MBH) reaction mediated by an enzymatic nucleophile (compare 3 3 1; Scheme 1).…”

Section: Synthetic Strategymentioning

confidence: 99%

“…Kirst also suggested that a transannular cyclization of a 1,3-dicarbonyl nucleophile may generate the C(3)OC (14) bond (3). Alternatively, we speculated that the C(3)OC (14) bond may be formed by a vinylogous Morita-Baylis-Hillman (MBH) reaction mediated by an enzymatic nucleophile (compare 3 3 1; Scheme 1). Based on these biosynthetic considerations, we sought to assemble spinosyn A (1) via a TDA and MBH cyclization sequence of an appropriately functionalized macrocyclic pentaene 4.…”

Section: Synthetic Strategymentioning

confidence: 99%

Total synthesis of (–)-spinosyn A

Mergott

Frank

Roush

2004

Proc. Natl. Acad. Sci. U.S.A.

127

View full text Add to dashboard Cite

A convergent, highly stereoselective total synthesis of (؊)-spinosyn A (1) is described. Key features of the synthesis include the transannular Diels-Alder reaction of macrocyclic pentaene 11 and the transannular Morita-Baylis-Hillman cyclization of 12 that generates tetracycle 26. The total synthesis of (؊)-spinosyn A was completed by a sequence involving the highly ␤-selective glycosidation reaction of 13 and glycosyl imidate 30.T he spinosyns are a family of polyketide natural products that possess extraordinary insecticidal activity. The biosynthetic mixture, generated by Saccharopolyspora spinosa, comprises mostly spinosyn A (1) (Scheme 1) (Ϸ85%) and spinosyn D (Ϸ10-15%) (1-8). This mixture is currently marketed for use as an insecticide against a variety of insects (6). Total syntheses of spinosyn A have been reported by Evans and Black (9) and Paquette et al. (10,11). Synthetic StrategyDiels-Alder reactions have been proposed as key steps in the biogenesis of several natural products, including lovastatin, solanapyrone, nargenicin, and ikarugamycin (12). Kirst et al. (3) suggested that the biosynthesis of spinosyn A may involve a transannular Diels-Alder (TDA) (13) reaction of a macrocyclic pentaene to form the C(4)OC(12) and C(7)OC (11) bonds (see 4 3 3; Scheme 1). Kirst also suggested that a transannular cyclization of a 1,3-dicarbonyl nucleophile may generate the C(3)OC (14) bond (3). Alternatively, we speculated that the C(3)OC(14) bond may be formed by a vinylogous Morita-Baylis-Hillman (MBH) reaction mediated by an enzymatic nucleophile (compare 3 3 1; Scheme 1). Based on these biosynthetic considerations, we sought to assemble spinosyn A (1) via a TDA and MBH cyclization sequence of an appropriately functionalized macrocyclic pentaene 4.Diastereoselectivity of the Diels-Alder Reaction. Paramount to the success of this synthetic strategy is the control of the diastereoselectivity of the TDA reaction (4 3 3). It is known from the work of Evans and Black (9) that the intrinsic diastereofacial selectivity of the intramolecular Diels-Alder (IMDA) reaction of 5a favors the incorrect C(7)OC(11) trans-fused diastereomer 6a with 6:1 selectivity (Scheme 2). Although Evans and Black (9) addressed this issue by incorporating a chiral auxiliary (13) in the dienophile (see 5b 3 7b), we would not have recourse to this strategy for the TDA cyclization of 4. Thus, some means for controlling the stereochemistry at the C(7)OC(11) ring fusion relative to the C(9)Oalkoxy substituent in the Diels-Alder reaction was required.We initially hoped to use the steric directing-group strategy to control the diastereoselectivity of the Diels-Alder reaction (15-17), which could involve appending a bromine steric directing group at C(6) of the IMDA or TDA substrate to control the stereochemical outcome of the cycloaddition, leading to the desired C(7)OC(11) trans-fused diastereomer. It was anticipated that TS2, which leads to the undesired C(7)OC(11) trans-fused isomer 10 and is favored in the absence of the C(6)OBr steric direct...

show abstract

Asymmetric Diels-Alder cycloaddition reactions with chiral .alpha.,.beta.-unsaturated N-acyloxazolidinones

Cited by 685 publications

References 1 publication

A chiral N-crontonyloxazolidinone Diels-Alder adduct

A chiral N-crontonyloxazolidinone Diels-Alder adduct

Natural amino acids as chiral auxiliaries in asymmetric Diels–Alder reactions

Total synthesis of (–)-spinosyn A

Contact Info

Product

Resources

About