Enantioselective Total Synthesis of 1-epi-Pathylactone A

Abstract

[structure: see text]. The first enantioselective total synthesis of 1-epi-pathylactone A, 3, has been accomplished using a PhI(OAc)2-mediated domino reaction as a key step. No diastereomeric separation was required throughout the whole synthetic scheme presented in this paper. Comparison of 1H and 13C NMR spectral data of the synthetic product with the reported spectral data of natural pathylactone A, coupled with an X-ray crystallographic analysis, led to the conclusion that the C1 configuration in the original paper was erroneously ascribed to (R).

Efficient Construction of Highly Substituted and Stereodefined cis‐Fused Lactones

“…Still, the most interesting facet of this reaction is the ease of subsequent mild base promoted ring‐system interchange, leading to highly functionalized cis ‐fused lactone frameworks. This approach provides easy access to the desired agarofuran building blocks, as starting unsaturated diols 1 (Scheme ) are readily available from ( S )‐(+)‐Wieland–Miescher ketone 2a…”

“…We then extended the synthetic usefulness of this domino1 approach to the synthesis of norsesquiterpene spirolactone–testosterone hybrids of type 6 starting from steroidal unsaturated diol 4a as the domino precursor. This provided a convenient route for the synthesis of 1‐ epi ‐pathylactone A ( 3a , R = OH),2a thus invalidating the assigned C1 configuration for pathylactone A,2c,2d the carbon skeleton of napalilactone ( 3b ),2e and the norsesquiterpene spirolactone–testosterone hybrid 6 2b…”

Microwave‐Assisted Competing Domino Processes in the Octaline Diol Series

“…With PhMe or H 2 O as solvent (domino conditions D and E), only the glycal-type half-cascade products (i.e., 2, 6, 10, 13, 16) were obtained, irrespective of the nature of the angular substitution. These compounds, whose synthetic utility was explored, [12] are also cleanly obtained in PhMe by using PhI(OAc) 2 as the domino promoter. In AcOH, treatment of unsaturated diols 1b-h with Pb(OAc) 4 under all domino conditions (A, B or C) gave no detectable quantities of ring-expanded structures.…”

2,8-Diheterobicyclo[3.2.1]octane Ring Systems: Natural Occurrence, Synthesis and Properties

“…This methodology could be easily applied to the synthesis of natural products such as 1-epi-pathylactone A, 37 with the conversion of diol 5 into 2,8-dioxabicyclo[3.2.1]octane 6 as a key step (Scheme 13), the carbon skeleton of agarofuran sesquiterpene compounds, 38 40 Their methodology provides useful scaffolds for target-oriented synthesis, including macrocyclic furans and polyhydroxylated azepanes (Scheme 14). It is worth mentioning that the pyrrole moiety can be used instead of furan, and thus they were also able to synthesize compounds with an aza/aza[3.2.1] core.…”