5 research outputs found
Construction of the Azacyclic Core of Tabernaemontanine-Related Alkaloids <i>via</i> Tandem Reformatsky–Aza-Claisen Rearrangement
A divergent
synthetic methodology for a tabernaemontanine-related
alkaloid was developed. The synthetic route features practical improvements
in the Pictet–Spengler cyclization for the tetrahydro-β-carboline
intermediate and an unprecedented tandem Reformatsky–aza-Claisen
rearrangement to create the core carbon skeleton and stereochemistries
of tabernaemontanine-related alkaloids
Construction of the Azacyclic Core of Tabernaemontanine-Related Alkaloids <i>via</i> Tandem Reformatsky–Aza-Claisen Rearrangement
A divergent
synthetic methodology for a tabernaemontanine-related
alkaloid was developed. The synthetic route features practical improvements
in the Pictet–Spengler cyclization for the tetrahydro-β-carboline
intermediate and an unprecedented tandem Reformatsky–aza-Claisen
rearrangement to create the core carbon skeleton and stereochemistries
of tabernaemontanine-related alkaloids
Stereoselective Synthesis of 1,4,5-Tri-<i>cis</i>-guaiane Sesquiterpene: First Total Synthesis of (−)-Dendroside C Aglycon
The
first total synthesis of (−)-dendroside C aglycon, consisting
of a 1,4,5-tri-<i>cis</i>-guaiane skeleton, from a versatile
hydroazulene intermediate has been accomplished. The key features
of the syntheses include the stereoselective preparation of the unusual <i>cis</i>-hydroazulene core via a sequence of a unique Dieckmann
condensation of the bicyclic lactone system, which was concisely prepared
by the tandem conjugate addition and intramolecular allylic alkylation
of a butenolide precursor, and construction of the characteristic
tricyclic skeleton by a carbene-mediated cyclopropanation
Asymmetric Total Synthesis of (+)-Intricenyne via an Endocyclization Route to Oxocane Skeleton
The
first total synthesis of (+)-intricenyne consisting of an oxocane
skeleton was achieved via an extremely selective endocyclization strategy.
The key features of the synthesis include a regio- and diastereoselective
epoxide opening reaction, concise elaboration of oxocane cores via
abnormally selective endocyclization ether ring formation, and versatile
incorporation of the labile functional groups
Asymmetric Total Synthesis of (+)-(3<i>E</i>)‑Pinnatifidenyne via Abnormally Regioselective Pd(0)-Catalyzed Endocyclization
The
asymmetric total synthesis of the marine natural product (+)-(3<i>E</i>)-pinnatifidenyne was accomplished. The key features of
the synthesis involve the construction of an eight-membered cyclic
ether by the abnormally regioselective Pd(0)-catalyzed cyclization,
the installation of a double bond in the oxocene skeleton by sequential <i>in situ</i> deconjugative isomerization, and the efficient introduction
of the crucial chloride mediated by the substrate-controlled diastereoselective
reduction