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Several phosphonate Wittig reagents were synthesized and treated with aldehydes and an activated ketone under mild conditions to obtain alpha,beta-unsaturated phosphonates and their corresponding phosphonic acids. An example was the preparation of an ylide, ((diethoxyphosphinyl)methylidene)triphenylphosphorane, from (diethoxyphosphinyl)methyl triflate through its phosphonium triflate salt.

Presents the synthesis of the Wittig reagent [(diethoxyphosphinyl)methylidene]triphenylphosphorane using its phosphonium triflate salt. Treatment of the reagent with various aldehydes and an activated ketone; Formation of cis and trans isomers; Hydrogenation of alpha, beta-unsaturated esters.

Three new dimeric polyketides, i.e., phaeochromycins I-K ( 1 - 3 , respectively) and a known polyketide phaeochromycin F ( 4 ), were isolated from the culture broth of a saline Qinghai-Tibet Plateau permafrost soil-derived Streptomyces sp. 166#. The structures were determined by analyzing one-dimensional and two-dimensional NMR as well as HRESIMS data. Compounds 2 and 3 exhibited a selective antiproliferative activity against H1299 and HUCCT1 cell lines, exhibiting IC 50 values ranging from 8.83 to 10.52 μM., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

A simple and efficient method for hydrotrifluoromethylation of unactivated alkenes was reported. The reaction relied on the single electron oxidation of a commercially available sodium trifluoromethanesulfinate (CF 3 SO 2 Na, Langlois' reagent) using Mn(OAc) 3 ·2H 2 O as the oxidant and the subsequent addition of trifluoromethyl radical to C═C double bonds. The reaction proceeded readily under mild conditions with good tolerance of a variety of functional groups in the substrates. The preliminary reaction mechanism was studied with deuteration, radical clock, and TEMPO inhibition experiments.

A chromatography-free, asymmetric synthesis of the C2-symmetric P-chiral diphosphine t-Bu-SMS-Phos was developed using a chiral auxiliary-based approach in five steps from the chiral auxiliary in 36% overall yield. Separtion and recovery of the auxiliary were achieved with good yield (97%) to enable recycling of the chiral auxiliary. An air-stable crystalline form of the final ligand was identified to enable isolation of the final ligand by crystallization to avoid chromatography. This synthetic route was applied to prepare up to 4 kg of the final ligand. The utility of this material was demonstrated in the asymmetric hydrogenation of trifluoromethyl vinyl acetate at 0.1 mol % Rh loading to access a surrogate for the pharmaceutically relavent chiral trifluoroisopropanol fragment in excellent yield and enantiomeric excess (98.6%).

A new chiral sulfinyl transfer auxiliary derived from readily available phenylglycine was developed. This auxiliary is utilized to synthesize a diverse array of alkyl- and arylsulfinamides and sulfinylferrocenes in high yields and excellent ee's. The desired products are produced in a one-pot sequence from the oxathiazolidine 2-oxide by two sequential nucleophilic additions that proceed in a stereospecific manner.

A novel ruthenium carbene-catalyzed epimerization of vinylcyclopropanes is reported. The reaction rate strongly depends on the presence of ruthenium ligands in solution. When the first-generation Grubbs catalyst is employed, a 5.3:1 equilibrium ratio of epimers is established quickly, but when a first-generation Hoveyda catalyst is employed, epimerization is observed only if an additional phosphine or nitrogen ligand is added. NMR and kinetic studies suggest that the isomerization reaction occurs through the intermediacy of a ruthenacyclopentene. The observation suggests that cyclopropylmethylidene ruthenium carbenes of synthetic utility may be accessible via ruthenacyclopentenes obtained via other routes.