Synthesis of α-Amino Acids and DerivativesRelated

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Phase-transfer-catalyzed alkylation of glycinate Schiff base with racemic secondary alkyl halides proceeded with excellent levels of synand enantioselectivities under the influence of a chiral quaternary ammonium bromide and 18- crown-6. The alkylation product can be selectively converted to the corresponding anti isomer, allowing the preparation of all the stereoisomers of β-alkyl-α-amino acid derivatives.

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Nội dung Text: Synthesis of α-Amino Acids and DerivativesRelated

Synthesis of α-Amino Acids and Derivatives Related: Name Reactions Petasis Reaction Recent Literature Diethyl N-Boc-iminomalonate, prepared on
multi-gram scale, served as a stable and highly reactive electrophilic glycine equivalent which reacted with organomagnesium compounds affording substituted aryl N-Boc- aminomalonates. Subsequent hydrolysis produced arylglycines. P. Cali, M. Begtrup, Synthesis, 2002, 63-64. Using a cinchonine-derived alkaloid catalyst, enantioselective alkylations of N- (diphenylmethylene) glycine tert-butyl ester were efficiently carried out with various alkyl halides to give products in high enantiomeric excess. W. He, Q. Wang, Q. Wang, B. Zhang, X. Sun, S. Zhang, Synlett, 2009, 1311-1314.
Phase-transfer-catalyzed alkylation of glycinate Schiff base with racemic secondary alkyl halides proceeded with excellent levels of syn- and enantioselectivities under the influence of a chiral quaternary ammonium bromide and 18- crown-6. The alkylation product can be selectively converted to the corresponding anti isomer, allowing the preparation of all the stereoisomers of β-alkyl-α-amino acid derivatives. T. Ooi, D. Kato, K. Inamura, K. Ohmatsu, K. Maruoka, Org. Lett., 2007, 9, 3945-3948. A new method for the Rh(I)-catalyzed addition of arylboronic acids to chiral N-tert-
butanesulfinyl imino esters allows the asymmetric synthesis of arylglycine derivatives in high yields and diastereoselectivities for various functionalized arylboronic acids. M. A. Beenen, D. J. Weix, J. A. Ellman, J. Am. Chem. Soc., 2006, 128, 6304-6305. A cationic palladium-complex catalyzes the addition of arylboronic acids to N-tert- butanesulfinyl iminoacetates to yield optically active arylglycine derivatives with good yield and high diastereoselectivity. This reaction provides a convenient and efficient method for the synthesis of arylglycine derivatives. H. Dai, X. Lu, Org. Lett., 2007, 9, 3077-3080. An efficient method for the asymmetric synthesis of anti-β-hydroxy-α-amino acid
derivatives is based on highly enantio- and diastereoselective aldol reactions of the silicon enolate derived from N-trifluoroacetylglycinate with aldehydes using a chiral zirconium catalyst. J. Kobayashi, M. Nakamura, Y. Mori, Y. Yamashita, S. Kobayashi, J. Am. Chem. Soc., 2004, 126, 9192-9193. A highly efficient direct asymmetric aldol reaction of a glycinate Schiff base with aldehydes has been achieved under mild biphasic conditions with excellent stereochemical control, using a chiral quaternary ammonium salt as a phase-transfer catalyst. T. Ooi, M. Kameda, M. Taniguchi, K. Maruoka, J. Am. Chem. Soc., 2004, 126, 9685-9694. A copper(I)-catalyzed direct three-component coupling of ethyl glyoxylate, p-anisidine, and
terminal alkynes provides β,γ-alkynyl α-amino acid derivatives in good yields. Z. Shao, A. S. C. Chan, Synthesis, 2008, 2868- 2870. The regioselective opening of Bn2N-α- methylserine-β-lactone with organocuprates gave enantiopure α-methyl amino acids in excellent yields. N. D. Smith, A. M. Wohlrab, M. Goodman, Org. Lett., 2005, 7, 255-258. In the presence of a catalytic amount of Cu(OTf)2 and a chiral diamine ligand, various N-acylimino esters reacted smoothly with silyl enol ethers and alkyl vinyl ethers to afford the corresponding Mannich-type adducts in high yields with high diastereo- and enantioselectivities. The reaction mechanism is discussed.
S. Kobayashi, R. Matsubara, Y. Nakamura, H. Kitagawa, M. Sugiura, J. Am. Chem. Soc., 2003, 125, 2507-2515. Both (3R,5R)-5-methyl-3-pyrrolidinecarboxylic acid and (R)-3-pyrrolidinecarboxylic acid efficiently catalyzed the Mannich-type reactions of aldehydes with α-imino esters under mild conditions and afforded anti-Mannich products with high diastereo- and enantioselectivities. H. Zhang, S. Mitsumori, N. Utsumi, M. Imia, N. Garcia-Delgado, M. Mifsud, K. Albertshofer, P. H.-Y. Cheong, K. N. Houk, F. Tanaka, C. F. Barbas, III, J. Am. Chem. Soc., 2008, 130, 875- 886. Direct catalytic, enantioselective, anti-selective Mannich-type reactions between unmodified ketones and α-imino esters using 5-10 mol % of (R)-3-pyrrolidinecarboxylic or (R)-β-proline as
catalyst in 2-PrOH at room temperature gave products in good yields with high diastereo- and enantioselectivities. H. Zhang, M. Mifsud, F. Tanaka, C. F. Barbas, III, J. Am. Chem. Soc., 2006, 128, 9630-9631. Proline-catalyzed Mannich-type reactions of N- PMP-protected α-imino ethyl glyoxylate with a variety of unmodified ketones provided functionalized α-amino acids in high yields with excellent regio-, diastereo-, and enantioselectivities. In reactions involving ketone donors where diastereoisomeric products could be formed, two adjacent stereogenic centers were created simultaneously upon carbon-carbon bond formation with complete syn-stereocontrol. A. Cordova, W. Notz, G. Zhong, J. M. Betancort, C. F. Barbas, J. Am. Chem. Soc., 2002, 124, 1842-1843.
Proline-catalyzed Mannich-type reactions of N- PMP-protected α-imino ethyl glyoxylate with a variety of unmodified aliphatic aldehydes provided functionalized α-amino acids in high yields with excellent enantioselectivities. The diastereoselectivity of the reaction increased with the bulkiness of the substituents of the aldehyde donor. A. Cordova, W. Notz, G. Zhong, J. M. Betancort, C. F. Barbas, J. Am. Chem. Soc., 2002, 124, 1866-1867. A direct highly anti-selective and enantioselective asymmetric Mannich reaction using a novel axially chiral amino trifluoromethanesulfonamide has been developed. Reactions between aldehydes and N- PMP-protected α-imino ethyl glyoxylate proceed smoothly to give β-amino aldehydes
with high anti/syn ratio and enantioselectivity. T. Kano, Y. Yamaguchi, O. Tokuda, K. Maruoka, J. Am. Chem. Soc., 2005, 127, 16408- 16409. (3R,5R)-5-methyl-3-pyrrolidinecarboxylic acid as catalyst for Mannich-type reactions afforded anti-products in good yields with excellent diastereo- and enantioselectivities under mild conditions and low catalyst loadings. S. Mitsumori, H. Zhang, P. H.-Y. Cheong, K. N. Houk, F. Tanaka, C. F. Barbas, III, J. Am. Chem. Soc., 2006, 128, 1040-1041. Chelated amino acid ester enolates are excellent nucleophiles for allylic alkylations. With these enolates, even terminal π-allyl palladium complexes react without significant isomerization.
K. Krämer, U. Kazmaier, J. Org. Chem., 2006, 71, 8950-8953. A Lewis acid-catalyzed three-component, mild, highly atom econocial, direct-type Mannich reaction of simple aromatic and enolizable aliphatic aldehydes, secondary amines, and glycine derivatives affords various synthetically important anti-α,β-diamino ester derivatives in high yields with high diastereoselectivities. M. M. Salter, J. Kobayashi, Y. Shimizu, S. Kobayashi, Org. Lett., 2006, 8, 3533-3536. Chiral complexes of calcium promote asymmetric 1,4-addition reactions and [3+2] cycloaddition reactions of α-amino acid derivatives with α,β-unsaturated carbonyl compounds. The reactions proceeded smoothly
in the presence of 5-10 mol % of the chiral calcium catalyst to afford the desired adducts in high yields with high diastereo- and enantioselectivities. S. Saito, T. Tsubogo, S. Kobayashi, J. Am. Chem. Soc., 2007, 129, 5364-5365. Homoallylic α-amino esters and amines were prepared via a Pd(II)-catalyzed coupling of 1,2- nonadiene and boronic acids with ethyl iminoacetate or aliphatic, aromatic, and heteroaromatic imines. C. D. Hopkins, H. C. Malinakova, Org. Lett., 2006, 8, 5971-5974.