Polyhydroxylated pyrrolidine and pyrrolizidine alkaloids from Hyacinthoides non-scripta and Scilla campanulata

General Intermediates for the Synthesis of 6-C-Alkylated DMDP-Related Natural Products

“…Single-crystal X-ray diffraction was collected on a Rigaku RAPID-AUTO diffractometer. (11). To a solution of alkene en-9 (0.22 g, 0.39 mmol) in acetonitrile (3 mL), iodine (0.36 g, 1.4 mmol) was slowly added, and the resulting purple mixture was stirred at r.t. for 3.5 h. The reaction was then quenched by adding sat.…”

“…Another 6-Calkyl-DMDP example is 2,5-dideoxy-2,5-imino-glycero-D,L-manno-heptitol (homo-DMDP, 4, Figure 1), which was synthesized by the Wong group [9] in 1995 before it was isolated in 1997 [10] from Hyacinthaceae plants. In addition, 7-O-glycosylated homoDMDP natural products such as OPEN ACCESS homoDMDP-7-O-apioside (5, Figure 1) and homoDMDP-7-O-β-D-xyloside (6, Figure 1), isolated from bluebell, also showed very highly selective glycosidase inhibition properties [11]. Interestingly, the stereochemistry at C-6 of the above mentioned 6-C-alkyl-DMDP natural products was not reported upon their isolation owing to limitations on NMR analysis due to the scarce amounts of substance available from natural sources.…”

Isolation, Biological Activities, and Synthesis of the Natural Casuarines

“…(1)) [7]. This group also includes, australine [8], alexine [9] (7a-epi-australine), several other epi-australines (1-epiaustraline, 3-epi-australine [10], 2,3-diepi-australine, 2,3,7-tri-epiaustraline) [11], 1-epi-australine-2-O--glucoside and the more recently isolated hyacinthacine alkaloids of which nineteen novel compounds have been identified [12]. This group, along with the polyhydroxylated pyrrolidine, piperidine, indolizidine and nortropane alkaloids, have glycosidase inhibitory activities and thus have potential utility as antiviral, anticancer, antidiabetic and antiobesity drugs [7].…”

A New Synthetic Approach to (+)‐Hyacinthacine A1 and the First Total Synthesis and Absolute Configuration Assignment of Naturally Occurring (+)‐Hyacinthacine A6

“…[2] The first examples of this family were alexine, isolated in 1988 from Alexa leiopetala by Nash et al, [3] and australine, isolated in the same year from the seeds of Castanospermum australe by Molyneux et al [4] (see Figure 1). More recently, a series of hyacinthacines have been isolated from bluebells (Hyacinthoides non-scripta), [5] grape hyacinths (Muscari armeniacum) [6] and from the bulbs of Scilla sibirica, [7] Scilla peruviana [8] and Scilla socialis [9] by Asano and co-workers. unsaturated ester 8 or ketone 9, which were submitted to internal lactamization and reductive amination, respectively, to give the corresponding intermediate pyrrolizidin-5-one 11 and the totally protected pyrrolizidine 14.…”