796853-19-5

Upstream product

• 157967-07-2 (2S,3S,4S)-3-(N-tert-butoxycarbonyl-2'-pyrrolidinyl)-3-methoxy-2-methylpropanoic acid 
• 147-85-3 L-proline 
• 158111-34-3 <2S-<2R*<(R*),α(S*),β(R*)>>>-1-<(1,1-Dimethylethoxy)carbonyl>-β-hydroxy-α-methyl-2-pyrrolidinepropanoic acid 2-hydroxy-1,2,2-triphenylethyl ester 
• 15761-39-4 1-(tert-butoxycarbonyl)-L-proline 
• 158111-36-5 <2S-<2R*<(R*),α(S*),β(R*)>>>-1-<(1,1-Dimethylethoxy)carbonyl>-β-methoxy-α-methyl-2-pyrrolidinepropanoic acid 2-hydroxy-1,2,2-triphenylethyl ester 
• 69610-41-9 Boc-L-Pro-H 
• 69610-40-8 N-(tert-butoxycarbonyl)-L-prolinol 
• 796853-44-6 ethyl (2R,3S,4S)-3-(N-tert-butoxycarbonyl-2'-pyrrolidinyl)-3-methoxy-2-methylpropanoate 
• 796853-20-8 ethyl (2R,3S,4S)-3-(N-tert-butoxycarbonyl-2'-pyrrolidinyl)-3-hydroxy-2-methylpropanoate 

Relevant academic research and scientific papers

Synthesis of both syn and anti diastereoisomers of Boc-dolaproine from (S)-proline through DKR using ruthenium-catalyzed hydrogenation: A dramatic role of N-protecting groups

The natural (2R,3R)-Boc-dolaproine and its unnatural (2S,3S) diastereoisomer were synthesized involving as key transformation the Ru(II)-promoted hydrogenation of the β-keto-α-methyl ester derived from (S)-N-Boc-proline. Interestingly, the asymmetric hydrogenation of this β-keto ester N-protected as an amine hydrochloride salt, provided the corresponding anti (2S,3R)- and (2R,3S)-β-hydroxy-α-methyl esters with significant level of selectivities through dynamic kinetic resolution. Graphical Abstract.

The Dolastatins. 17. Synthesis of Dolaproine and Related Diastereoisomers

A special challenge in accomplishing the total synthesis of dolastatin 10 (1) entailed deducing the absolute configuration of the new β-methoxy-γ-amino acid component dolaproine (2) as 2S,2'R,3'R and devising a stereoselective synthesis.Synthesis of this unusual (S)-proline-derived unit as its N-tert-butoxycarbonyl derivative (9b) and three stereoisomers (9a, 9c, 9d) has been summarized.The diastereoisomers were assembled by an aldol condensation between aldehyde 5, derived from (S)-proline, with chiral propionate 6, followed by methylation and cleavage of the chiral directing ester group by hydrogenolysis to afford methyl ethers 9a-d.The absolute stereochemistry of the diastereoisomers was determined by a combination of X-ray crystallographic analyses (of 9a and lactam 11b formed from isomer 7a) and high-field (400 MHz) NMR studies.By using each of these isomers in a series of dolastatin 10 syntheses the stereochemistry of the dolaproine (2) unit of natural (-)-dolastatin 10 (1) was shown to be 2S,2'R,3'R.