- Synthesis of (-)-dihydropinidine, (2S,6R)-isosolenopsin and (+)-monomorine via a chiral synthon from l-aspartic acid
-
The use of a β-amino aldehyde derived from l-aspartic acid as a chiral synthon to construct 2,6-disubstituted piperidines is described. The synthesis of (-)-dihydropinidine·HCl, (2S,6R)-isosolenopsin·HCl and (+)-monomorine has been achieved from this chiral synthon using a Wittig reaction followed by hydrogenation (reductive cyclization) as the key steps.
- Reddy, Chada Raji,Latha, Bellamkonda
-
p. 1849 - 1854
(2012/02/05)
-
- Manipulating L-aspartic and L-glutamic acids - Diastereoselective synthesis of enantiopure β-amino-γ-hydroxy acids and γ-amino-δ-hydroxy acids
-
Enantiopure (3S,4R)- and (3S,4S)-3-amino-4-hydroxyhexanoic acids and (4S,5R)- and (4S,5S)-4-amino-5-hydroxyheptanoic acid derivatives have been prepared by stereodivergent synthesis from L-aspartic and L-glutamic acids, respectively. The stereochemistry at the carbon atom attached to the amino group was determined from the starting material but the configuration at C-4 or C-5 is controlled by diastereoselective alkylation with diethylzinc or ethylmagnesium bromide. The protection of the carboxylic group as OBO orthoester improved the yields in the final products. Wiley-VCH Verlag GmbH & Co, KGaA, 69451 Weinheim, Germany, 2003.
- Andres, Jose M.,Munoz, Eva M.,Pedrosa, Rafael,Perez-Encabo, Alfonso
-
p. 3387 - 3397
(2007/10/03)
-
- General Route to 2,4,5-Trisubstituted Piperidines from Enantiopure ss-Amino Esters. Total Synthesis of Pseudodistomin B Triacetate and Pseudodistomin F
-
The Michael addition reaction of enantiopure ss-amino esters with methyl acrylate followed by Dieckmann condensation and enol silylation affords the enol ethers 6, which are hydrogenated with catalysis by Raney-Ni at 80 atm and 80°C to provide 2,4,5-trisubstituted piperidines with high diastereoselectivity. In this case Ni-H attacks the C-C double bond from the direction of the 2-alkyl group to provide the products in which 2,4,5-trisubstrited groups are all cis to each other. While hydrogenation of enol ether 13 without a N-Boc protecting group gives the product 15 in which the 4-hydroxy group and 5-ester moiety are trans to the 2-alkyl group. By using the diastereoselective hydrogenation products 9d and 9e as key intermediates, pseudodistomin B triacetate and pseudodistomin F are synthesized. The key steps for these transformations include Curtius rearrangement and Julia olefination.
- Ma, Dawei,Sun, Haiying
-
p. 6009 - 6016
(2007/10/03)
-
- The total synthesis of L-daunosamine
-
N,O-Dibenzyl-N-tert-butoxycarbonyl-L-homoserinal (7), obtained from L-aspartic acid, reacts with vinylmagnesium chloride to afford with high stereoselectivity compound 6 which is subsequently transformed into the derivative of L
- Jurczak, Janusz,Kozak, Janusz,Golebiowski, Adam
-
p. 4231 - 4238
(2007/10/02)
-