116174-63-1Relevant articles and documents
Enantioselective synthesis of: Anti -3-alkenyl-2-amido-3-hydroxy esters: Application to the total synthesis of (+)-alexine
Yu, Lu,Somfai, Peter
, p. 2799 - 2802 (2019)
A straightforward synthesis of anti-3-alkenyl-2-amido-3-hydroxy esters from the corresponding racemic α-amino-β-keto esters by using a ATH/DKR protocol has been developed. This method gives moderate to excellent yields with high chemo-, diastereo- and enantioselectivities for a broad range of substrates. In order to highlight the versatility of the methodology it was applied in an efficient asymmetric synthesis of the polyhydroxylated pyrrolizidine alkaloid (+)-alexine.
Total Syntheses of (-)-7- epi -Alexine and (+)-Alexine Using Stereoselective Allylation
Ham, Won-Hun,Jung, Changyoung,Myeong, In-Soo
, p. 3471 - 3476 (2019)
Total syntheses of (-)-7- epi -alexine and (+)-alexine were achieved by using stereoselective allylation via a functionalized pyrrolidine obtained from an extended chiral 1,3-oxazine. The synthetic strategies include pyrrolidine formation via oxazine cleavage and diastereoselective allylations of a pyrrolidine aldehyde. (-)-7- epi -Alexine and (+)-alexine were synthesized from anti, syn, anti -oxazine in 12 steps.
Total synthesis of (+)-alexine by utilizing a highly stereoselective [3+2] annulation reaction of an TV-tosyl-α-amino aldehyde and a 1,3-bis(silyl)propene
Dressel, Martina,Restorp, Per,Somfai, Peter
scheme or table, p. 3072 - 3077 (2009/04/11)
A novel route towards the polyhydroxylated pyrrolizidine alkaloid (+)-alexine has been developed. A key step in this synthesis is a highly stereoselective [3+2] annulation reaction of N-Ts-α-amino aldehyde 7a (Ts=tosyl) and 1,3-bis(silyl)propene 8a for the construction of the polyhydroxylated pyrrolidine subunit of the target molecule. Previous synthetic strategies rely on carbohydrates that require several protecting-group manipulations, there-by making the total number of steps relatively high. The [3+2] annulation strategy compares favorably with carbohydrate-based syntheses and constitutes a highly efficient entry to polyhydroxylated alkaloids.
New asymmetric strategy for the total synthesis of naturally occurring (+)-alexine and (-)-7-epi-alexine
Takahashi, Masaki,Maehara, Tetsuya,Sengoku, Tetsuya,Fujita, Norifumi,Takabe, Kunihiko,Yoda, Hidemi
, p. 5254 - 5261 (2008/09/21)
A novel and highly convenient process is described for the asymmetric synthesis of polyhydroxylated pyrrolizidine alkaloids, (+)-alexine [(1R,2R,3R,7S,7aS)-3-hydroxymethyl-1,2,7-trihydroxypyrrolizidine] and (-)-7-epi-alexine [(1R,2R,3R,7R,7aS)-3-hydroxymethyl-1,2,7-trihydroxypyrrolizidine], as the potent glycosidase inhibitors by featuring the efficient and stereodefined elaboration of the functionalized pyrrolidine derivatives, which were, in turn, prepared via stereoselective manipulation of the homochiral allyl alcohol precursors derived from l-xylose.
Asymmetric total synthesis of natural pyrrolizidine alkaloid, (+)-alexine
Yoda,Katoh,Takabe
, p. 7661 - 7665 (2007/10/03)
The total synthesis of the potent glycosidase inhibitor (+)-alexine with five contiguous stereogenic centres [(1R,2R,3R,7S,7aS)-3-hydroxymethyl-1,2,7-trihydroxypyrrolizidine alkaloid] is described featuring the efficient and stereodefined novel elaboratio