Asymmetric total synthesis of the individual diastereoisomers of hypoglycin A.

Impact of seed size on residual hypoglycin levels in ackee

“…Elution with water, concentration of the eluent, decolorization with activated charcoal and repeated crystallizations (80% ethanol) yielded HGA (N99% purity). The NMR data (obtained on a Bruker ACE 200 and Bruker Avance 500 spectrometers, Bruker BioSpin Corporation, Karlsruher, Germany) were consistent with literature values (Baldwin, Adlington, Bebbington, & Russell, 1994). HGB (purityN 99%) was obtained from Dr. Camille Bowen-Forbes and was used as a standard (C. S. Bowen-Forbes & Minott, 2009).…”

Structural characterization of hypoglycin B, a diastereomeric dipeptide from the ackee fruit (Blighia sapida Koenig) by NMR experiments

“…The compounds are present in both the arilli and seeds of the fruit. [5] HGA concentration in the arilli decreases as the fruit matures to a safe level in the ripe fruit. [6] Hypoglycin B (γ -L-glutamyl-α-amino-β-methylene cyclopropyl propionic acid, HGB, 2) (Fig.…”

“…1 H and 13 C NMR assignments for 1a and 1b were made with the help of gCOSY, gHSQC and gHMBC data, and were consistent with those found in the literature. [5] Stereochemical assignments were proposed tentatively on the basis of comparison of NMR spectral data with those published in the literature ( Table 2). The stereochemistry for compound 2 could not be elucidated because the 1 H NMR signals for the two isomers were coincident, as indicated by the gHSQC experiment.…”

Synthesis of 1,3‐Difunctionalized Cyclopentenes and 1,3,5‐Trifunctionalized Cyclohexanes by Silicon‐Induced Domino Reactions

“…This was demonstrated by the extension of the approach to cyclohexane synthesis (Scheme ). The required starting materials are allyloxiranes 15 , which can be obtained by a modification of a published procedure 11. The key step is an alkylation of lithiated alkenes 13 by epichlorohydrin.…”