Enantioselective Total Synthesis of the Reported Structures of (−)‐9‐epi‐Presilphiperfolan‐1‐ol and (−)‐Presilphiperfolan‐1‐ol: Structural Confirmation and Reassignment and Biosynthetic Insights

Four-Step Access to the Sesquiterpene Natural Product Presilphiperfolan-1β-ol and Unnatural Derivatives via Supramolecular Catalysis

“…3(14) 21.3 3C4 -3895.1 9-4929(2) -2801.0(16) 23.8 4C6 -3494.5 10-5169(2) -3448. 1(16) 24.6 3C8 -4308.0(9) -5276(2) -1381.8 (15) 21.4 3C9 -3590.5 9-4810(2) 4.6(16) 24.1 4C12 -3280.9 9-7451(2) -1092.1 (15) 23.8 3C13 -4598.9 10-3457(2) -2064.6(17) 25.9 4C16 -4700.4 10-7645(2) -3113.8 1727.7 4C17 -3877.4 10-3187 3343.0(17) 31.1 4C19 -4195.3 10 72.2(6) 27.2 70.1 6N7 40.7 (8) 27.0(8) 37.4 91.3 (6) 30.6(8) 1.8 7C10 20.9 (7) 28.9 (8) 19.6(7) 0.5 711.1(6) 1.6(7) C1 21.8 (7) 23.0(8) 20.6(7) -0.2(6) 13.0(6) -0.6(6) C4 22.6(7) 27.2 (9) 22.7(8) 0.8 (6) 13.7(7) -1.3 (7) C6 27.4 (8) 26. 4(8) 25.0(8) 2.2 (7) 18.0(7) -0.7 7C8 18.7 725.5 (8) 22.4 70.1 713.2(6) -0.4 6C9 20.5 728.8 (9) 24.0(8) -6.0(6) 13.3 7-3.0(6) 3 was selected and mounted on a mylar loop in perfluoroether oil on an Bruker APEX-II CCD diffractometer.…”

“…Cyclase enzymes exercise control over the terpene cyclization pathway via their cavity shape, which facilitates specific substrate folding, 8 as well as via specific interactions with active site amino acid residues and cofactors. 9 However, as recently argued by Tantillo, 10 evidence from gas-phase computational studies indicates that not every step is enzyme catalysed, as the intrinsic reactivity of the cation itself can dictate the reaction outcome in some cases. We recognized that the resorcinarene capsule I could be utilized to exploit this inherent reactivity: identifying a key cationic intermediate and generating it within its confines should enable the downstream reactions.…”

A Concise Synthesis of Presilphiperfolane Core through a Tandem TMTU–Co‐Catalyzed Pauson–Khand Reaction and a 6π Electrocyclization Reaction (TMTU=Tetramethyl Thiourea)

“…The appealing structure and potential biological activity of this type of natural product has prompted synthetic chemists to develop routes toward their total synthesis, culminating in the racemic total synthesis of presilphiperfolan‐9α‐ol by Weyerstahl and co‐workers in 1996, and the asymmetric total synthesis of (‐)‐presilphiperfolan‐1α‐ol by Stoltz and co‐workers in 2012 . The key steps to Weyerstahl′s and Stoltz′s successes are the intramolecular Wittig reaction and Diels‐Alder reaction, respectively (eqs 1–2, Figure ).…”

Total Synthesis of 3-<i>epi</i>-Juruenolide C

“…34,38) These facts suggest that unexpected face-selective hydrogenation can proceed because of the steric hindrance of the 4-methyl group in 13, without the anticipated coordination of the 3-hydroxy group to the heterogeneous catalyst. Thus, the homogeneous Crabtree's catalyst 39) was subsequently used according to the report by Hong and Stoltz (Entry 3). 40) As a result, desired γ-lactone 1 was clearly ob- tained as the main product, albeit the facial selectivity of only 3 : 2.…”