Total synthesis of the marine polypropionates, siphonarienal, siphonarienone, and pectinatone

Development of α,α-Disubstituted Crotylboronate Reagents and Stereoselective Crotylation via Brønsted or Lewis Acid Catalysis

“…The vinyl Bpin unit of alcohol 36 was converted into E -vinyl bromide under the CuBr 2 -mediated bromination conditions, affording product 32 in 64% yield. The synthesis of vinyl stannane 34 commenced from aldol reaction of β-ketoester 37 and aldehyde 38 . The resulting aldol adduct was subjected to Dess–Martin oxidation to deliver product 39 in 41% yield over two steps.…”

Stereoselective syntheses of siphonarienal and siphonarienone

“…Spectroscopic data of both natural products 1 and 2 were in good agreement with those reported in the literature. 4d, 6,9,18 …”

“…4 Other methods include the Zr-catalyzed asymmetric carboalumination, 5 iterative application of CuI-Tol-BINAP-catalyzed asymmetric conjugate addition, 6 Burgess's Ir-catalyzed hydrogenation, 7 and Feringa's Josiphos-catalyzed conjugate addition 8 by employing a desymmetrization strategy, which involves the asymmetric hydroboration of a known meso-olefin using (À)-IPC 2 BH (diisopinocamphenyl-borane), PCC (@pyridinium chlorochromate), and Baeyer-Villiger oxidation reaction to set the stereochemistry of the trimethylnonyl unit, 9 and desymmetrization of meso-diol using Lipase-AK and vinyl acetate conditions. 10 However, herein we describe the utilization of a diastereoselective oxidative kinetic resolution using glucose oxidase from Aspergillus niger and an Evans asymmetric alkylation, which is an attractive method for the installation of methyl centers.…”

A Highly Stereoselective and Flexible Strategy for the Convergent Synthesis of Long‐Chain Polydeoxypropionates: Application towards the Synthesis of the Glycolipid Membrane Components Hydroxyphthioceranic and Phthioceranic Acid

“…MeI (7.00 mL, 111 mmol, 1.80 equiv) was added at À78 8C within 15 min and the reaction mixture was stirred additional three hours at this temperature. The reaction was stopped by the addition of half saturated NH 4 Cl solution (400 mL) at À78 8C and warmed to room temperature. The aqueous phase was extracted with CH 2 Cl 2 (5 100 mL).…”

“…The biological activities of polydeoxypropionates are diverse and representative examples of this product class include the pectinatone, [4] the pheromones vittatalactone [5] and 4,6,8,10,16,18-hexamethyldocosane, [6] the cytotoxic natural products borrelidine [7] and doliculide, [8] as well as the long-chain aliphatic hydroxyphthioceranic acid (Scheme 1). [9] In light of the multitude of biological activities associated with deoxypropionates, substantial research efforts have been undertaken to develop synthetic tools for their stereoselective assembly.…”