6 research outputs found
Total Synthesis of Swinholide A: An Exposition in Hydrogen-Mediated C–C Bond Formation
Diverse
hydrogen-mediated C–C couplings enable construction
of the actin-binding marine polyketide swinholide A in only 15 steps
(longest linear sequence), roughly half the steps required in two
prior total syntheses. The redox-economy, chemo- and stereoÂselectivity
embodied by this new class of C–C couplings are shown to evoke
a step-change in efficiency
Highly Enantioselective Total Synthesis of (+)-Isonitramine
A new efficient enantioselective synthetic method of (+)-isonitramine is reported. (+)-Isonitramine was obtained in 12 steps (98% ee and 43% overall yield) from δ-valerolactam <i>via</i> enantioselective phase-transfer catalytic alkylation, Dieckman condensation, and diastereoselective reduction as key steps
Enantioselective Synthesis of Chiral α‑Thio-Quaternary Stereogenic Centers via Phase-Transfer-Catalyzed α‑Alkylation of α‑Acylthiomalonates
An
efficient synthetic method for establishing chiral α-thio-α-quaternary
stereogenic center was successfully developed. The enantioselective
α-alkylation of α-acylthiomalonates under phase-transfer
catalytic conditions [50% aq. KOH, toluene, −20 °C, and
(<i>S</i>,<i>S</i>)-3,4,5-trifluorophenyl-NAS
bromide] provided the corresponding α-acylthio-α-alkylmalonates
in high chemical yields (up to 99%) and high optical yields (up to
98% ee)
Enantioselective Synthesis of Chiral α‑Thio-Quaternary Stereogenic Centers via Phase-Transfer-Catalyzed α‑Alkylation of α‑Acylthiomalonates
An
efficient synthetic method for establishing chiral α-thio-α-quaternary
stereogenic center was successfully developed. The enantioselective
α-alkylation of α-acylthiomalonates under phase-transfer
catalytic conditions [50% aq. KOH, toluene, −20 °C, and
(<i>S</i>,<i>S</i>)-3,4,5-trifluorophenyl-NAS
bromide] provided the corresponding α-acylthio-α-alkylmalonates
in high chemical yields (up to 99%) and high optical yields (up to
98% ee)
Construction of Chiral α‑Amino Quaternary Stereogenic Centers via Phase-Transfer Catalyzed Enantioselective α‑Alkylation of α‑Amidomalonates
An
efficient enantioselective synthetic method for α-amido-α-alkylmalonates
via phase-transfer catalytic α-alkylation was successfully developed.
The α-alkylation of α-amidomalonates under phase-transfer
catalytic conditions (50% KOH, toluene, −40 °C) in the
presence of (<i>S</i>,<i>S</i>)-3,4,5-trifluorophenyl-NAS
bromide afforded the corresponding α-amido-α-alkylmalonates
in high chemical yields (up to 99%) and optical yields (up to 97%
ee), which could be readily converted to versatile chiral intermediates
bearing α-amino quaternary stereogenic centers. The synthetic
potential of this methodology was demonstrated via the synthesis of
chiral azlactone, oxazoline, and unnatural α-amino acid