15 research outputs found
Bioinspired total syntheses of terpenoids
Nature's highly efficient routes for constructing natural products have inspired chemists to mimic these processes in a laboratory setting. This Perspective presents some recent examples of conceptually different bioinspired total syntheses of complex terpenoids and thereby aims to highlight the vast benefits offered by bioinspired strategies
Recommended from our members
Calyciphylline B-type Alkaloids: Evolution of a Synthetic Strategy to (-)-Daphlongamine H.
We provide a full account of our synthetic studies targeting the hexacyclic calyciphylline B-type alkaloids, a subfamily of the Daphniphyllum natural products. Following an initial set of synthetic strategies focused on constructing the piperidine core of the calyciphylline B-type framework via a 6Ď€-azaelectrocyclization, as well as exploiting the reactivity of underexplored oxazaborinine heterocycles, we ultimately designed a highly functionalized acyclic precursor which underwent carefully orchestrated and efficient cyclizations to forge the architecturally complex natural product scaffold. Our efforts have culminated in the development of the first total synthesis of (-)-daphlongamine H, provided access to its C5-epimer, (-)-isodaphlongamine H, and led to structural revision of deoxyisocalyciphylline B
Recommended from our members
Calyciphylline B-type Alkaloids: Evolution of a Synthetic Strategy to (-)-Daphlongamine H.
We provide a full account of our synthetic studies targeting the hexacyclic calyciphylline B-type alkaloids, a subfamily of the Daphniphyllum natural products. Following an initial set of synthetic strategies focused on constructing the piperidine core of the calyciphylline B-type framework via a 6Ď€-azaelectrocyclization, as well as exploiting the reactivity of underexplored oxazaborinine heterocycles, we ultimately designed a highly functionalized acyclic precursor which underwent carefully orchestrated and efficient cyclizations to forge the architecturally complex natural product scaffold. Our efforts have culminated in the development of the first total synthesis of (-)-daphlongamine H, provided access to its C5-epimer, (-)-isodaphlongamine H, and led to structural revision of deoxyisocalyciphylline B
Recommended from our members
A Unified Strategy for the Enantiospecific Total Synthesis of Delavatine A and Formal Synthesis of Incarviatone A
We describe a symmetry-inspired synthetic approach that has enabled a short synthesis of delavatine A and a formal synthesis of incarviatone A, which are two likely biosynthetically related natural products. The indane core of these natural products was constructed through a cascade sequence involving five transformations that occur in a single pot. Leveraging symmetry has allowed us to trace both natural products back to a versatile building block, 3,5-dibromo-2-pyrone, and studies related to site-selective cross-coupling of this polyhalogenated heterocycle are described. In addition, our strategy gave access to a putative biogenetic precursor, from which the syntheses of both natural products were attempted
Total Synthesis of the Leucosceptroid Family of Natural Products
A highly efficient
strategy enabled the asymmetric total synthesis
of 15 antifeedant leucosceptroid natural products. The advanced tricyclic
core, available in gram quantity, served as the pivotal intermediate
for the preparation of norleucosceptroids B, C, F, and G and leucosceptroids
A, B, G, I, J, L, and M. Additionally, the bioinspired oxidative transformation
of leucosceptroid A to leucosceptroids C, K, O, and P using singlet
oxygen supports the hypothesis that leucosceptroids A and B are most
likely the biogenetic precursors of all other members of this natural
product family
A Bioinspired Cyclization Sequence Enables the Asymmetric Total Synthesis of Dictyoxetane
We have developed
the first synthesis of the unique oxetane containing
diterpene (+)-dictyoxetane. Our retrosynthetic planning was guided
by the putative biosynthesis of the unprecedented 2,7-dioxatricycloÂ[4.2.1.0<sup>3,8</sup>]Ânonane ring system. A bioinspired 4-<i>exo</i>-tet, 5-<i>exo</i>-trig cyclization sequence enabled the
construction of the synthetically challenging dioxatricyclic framework.
The overall synthesis proceeds in 15 linear steps from a known and
readily available <i>trans</i>-hydrindane fragment. In addition,
we were able to realize the first dyotropic rearrangement of an epoxide–oxetane
substrate
Synthesis of Quaternary α‑Methyl α‑Amino Acids by Asymmetric Alkylation of Pseudoephenamine Alaninamide Pivaldimine
The utility of pseudoephenamine as a chiral auxiliary for the alkylative construction of quaternary α-methyl α-amino acids is demonstrated. The method is notable for the high diastereoselectivities of the alkylation reactions, for its versatility with respect to electrophilic substrate partners, and for its mild hydrolysis conditions, which provide α-amino acids without salt contaminants. Alternatively, α-amino esters can be obtained by direct alcoholysis