Enantioselective Total Synthesis of the Highly Oxygenated 1,10‐seco‐Eudesmanolides Eriolanin and Eriolangin

Abstract

Sultones of swing: A sultone served as the key intermediate in the first enantioselective total syntheses of the bioactive title compounds (see scheme), the absolute configuration of which is now established. Starting from 2‐bromo‐1‐(2‐furyl)ethanone, 24 steps were required to generate the common basic structure, and in each case two additional steps yielded the natural products.

Natural sesquiterpenoids

“…261 An enantioselective synthesis of the 1,10-seco-eudesmanolides eriolanin and eriolangin has been achieved. 262 An enantiospecific total synthesis 263 and a conformational study 264 of valeranone have been carried out. In the latter work molecular mechanics calculations and nuclear magnetic resonance were utilized.…”

α-Alkylidene-γ-butyrolactone Formation via Bi(OTf)3-Catalyzed, Dehydrative, Ring-Opening Cyclizations of Cyclopropyl Carbinols: Understanding Substituent Effects and Predicting E/Z Selectivity

“…Synthesis of the ABL framework is an ongoing endeavor for the synthetic community. As such, several extensive reviews have been published highlighting the diverse approaches that can be taken toward the scaffold. ,, The general synthetic approaches to the ABL core have been classified into the following types: alkylidenation of γ-butyrolactones, various lactonization approaches, tandem (or sequential) intramolecular C–H insertion/olefination, the Dreiding–Schmidt organometallic approach, cross-methathesis between α-methylene-γ-butyrolactones and olefins, intramolecular enyne metathesis reactions, Pd-catalyzed cross-couplings, Diels–Alder and retro-Diels–Alder reactions, radical cyclizations, and Baeyer–Villiger reactions on cyclobutanones . Despite the abundant literature, the diversity within the ABLs has made the pursuit of strategic ABL targets and the development of methodologies to access them persistently meaningful endeavors in the synthetic community …”

Synthesis of α-Heteroarylpropanoic Acid via Asymmetric Hydroformylation Catalyzed by Rh(I)-(R,S)-BINAPHOS and the Subsequent Oxidation

“…For example, 2-(2-furyl)propanal could be a starting material for monensin, a polyether antibiotic . In addition, 2-(2-furyl)propanol, the reduction product of 2-(2-furyl)propanal, could be transformed into a series of antitumor, 1,10- seco -eudesmanolides 1 Asymmetric Hydroformylation of Vinylthiophenes a runsubstratetime (h) 2 : 3 b isolated yield of 2 (%)ee of 2 (%) 1 1a 3 94:6 93 ≥93 ( S ) c 2 1b 6 92:8 91 ≥91 ( R ) c 3 1c 3 95:5 92 95 ( S ) d 4 1d 6 84:16 68 88 ( R ) d a Reaction conditions: 1 (2.0 mmol), H 2 (1.0 MPa), CO (1.0 MPa), [Rh(acac)(CO) 2 ] (0.010 mmol), ( R,S )-MeO-BINAPHOS (0.040 mmol) in benzene (1.0 mL) at 60 °C.…”