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Silver-mediated direct trifluoromethoxylation of α-diazo esters and ketosteroid was disclosed. The reactions of alkyl α-diazo arylacetates with AgOCF3 or CF3SO2OCF3/AgF at −30 to 10 °C under a N2 atmosphere provided α-trifluoromethoxyl arylacetates in up to 90% yield, while alkyl α-diazo vinylacetates reacting with CF3SO2OCF3/AgF or AgOCF3 afforded γ-trifluoromethoxyl α,β-unsaturated esters in up to 94% yield. The α-diazo ketosteroid was also trifluoromethoxylated under the standard reaction conditions. This protocol allows for an effective and convenient access to a large number of synthetic building blocks, which are promising in the development of new functional OCF3-molecules.

Construction of difluoromethylthioethers (2) and difluorobis(arylthio)methanes (3) from RSX (X = SR, Cl, SO2Ph) and TMSCF2H in the absence of transition metals has been explored. The reaction is dramatically influenced by the nature of the base and the molar ratio of the reactants. Reactions between RSX and TMSCF2H in the presence of CsF provided 2 in good yields, whereas the reaction of RSX with TMSCF2H in the presence of t-BuOK afforded 3 in good yields. These protocols allow for convenient and efficient access to both difluoromethylthioethers and difluorobis(arylthio)methanes.

(E)-Bis(phosphonium)ethylenes were synthesized from aryl-, alkyl-, and arylalkylphosphines under solvent-free conditions using TfOCH2CF2H as reagent. The reaction allows for a convenient access to vinylenebis(trialkylphosphonium) salts in good to high yields.

An overview of reductive trifluoromethylation reactions using electrophilic ‘þCF3’ reagents Shi-Meng Wang , Jia-Bin Han , Cheng-Pan Zhang *, Hua-Li Qin *, Ji-Chang Xiao b,* a School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, 205 Luoshi Road, Wuhan 430070, China Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China

Oliganthins A (I), B (II), C (III) and D (IV) as well as the known gaudichaudione H are isolated from the stems of the title species.

Nam Ho Lee,* Jong Seok Baik, and Sung-bin HanDepartment of Chemistry, Cheju National University, Ara-1, Cheju 690-756, KoreaReceived May 29, 1999Oxygen molecule plays a pivot role in the biological sys-tems. In addition, it is probably the most desirable oxidant inorganic synthesis in terms of economical and environmentalviewpoints. Therefore, lots of efforts have long been focusedto utilize molecular oxygen for the oxidation of organiccompounds especially using transition metals as an activa-tor.

From the aerial parts of Salvia castanea Diels f. tomentosa Stib., four new hemiketal germacranolide sesquiterpenoids, castanins C-F (1 -4), were obtained as two pairs of interconvertible forms along with their acetates, 5 and 6. Their structures were elucidated by spectroscopic methods and X-ray analysis of the uninterconvertible isomeric acetates, 5 and 6. The computational study explained that the ratios of 1 and 2, 3 and 4, and their acetates (5 and 6) in the mixtures were 1:1, 1:2, and 1:3, respectively. In addition, the semisynthesis of castanins C (1) and D (2) was conducted by the photooxidation of castanin B (8), the major constituent of this plant. Compounds 5, 6, and 8 were also tested for their inhibitory activity toward MCF-7, HeLa, and HepG2 cell lines. (C) 2008 Elsevier Ltd. All rights reserved.

Two new bisnortriterpenoids with 18-norschiartane skeleton, wuweizidilactones G (1) and H (2), four new highly oxygenated nortriterpenoids based on a schisanartane skeleton, schindilactones DeG (3e6), a pre-schisanartane skeleton, pre-schisanartanin B (7), and a novel 3,4-seco-21,26-olide-artane triterpenoid wuweizilactone acid (8), along with 24 known terpenoids with different carbon frameworks, have been isolated from the acetone extract of the stems and leaves of Schisandra chinensis. The terpenoids produced by this plant have chemical diversity. The structures of new compounds 1e8 have been characterized by spectroscopic data interpretation. The cytotoxicity and anti-HIV-1 activity of all the Schisandra nortriterpenoids were evaluated.

Two new 6,7-seco-ent-kaurane diterpenoids, isojaponins A (1) and B (2), together with 18 known ent-kaurane diterpenoids were isolated from the aerial parts of Isodon japonicus. The structures of the two new compounds were elucidated by extensive 1D- and 2D-NMR spectroscopic methods in combination with MS experiments.

Isodon species (Labiatae) are widely distributed plants, many of which are used in folk medicine. Over the past twenty years, they have received considerable phytochemical and biological attention. Thestructures of their many diterpenoids constituents, especially those with an ent-kaurane skeleton, have been elucidated. The significant phytochemical and pharmacological diterpenoids form the subject of this review. There are 290 references.

Two new benzofuran glycosides, called psoralenoside and isopsoralenoside, were isolated from the fruits of Psoralea corylifolia, together with nine known compounds. Their structures were elucidated by detailed spectral analyses including extensive two dimensional (2D) NMR spectra.

Five new ent-kaurane diterpenoids xindongnins H-L (1-5), together with five known ones, xindongnins A and B (6, 7), melissoidesins G (8), dawoensin A (9), and glabcensin V (10) were isolated from Isodon rubescens var. rubescens. Their structures were elucidated by spectroscopic methods including extensive 2D NMR techniques.

Two new diterpenoids, rubescensin S (=(1alpha,6beta,14beta)-7alpha,20-epoxy-1,7,14-trihydroxy-16-oxo-15,16-seco-entkauran-6,15-olide; 1) and rubescensin T (=(1alpha,6beta,11beta,20S)-7alpha,20-epoxy-1,6,7-trihydroxy-20-methoxy-8,15-seco-ent-kaur-16-en-11,15-olide; 2) were isolated from the Chinese medicinal herb Isodon rubescens var. taihangensis. Compound 1 possesses a unique, unprecedented 15,16-seco-ent-kaurane skeleton. Both compounds exhibited cytotoxic activities against K562 human leukemia cells.

Three new 11beta,16beta-epoxy-ent-kauranoids melissoidesins 1-K (1-3) and one new ent-abietanoid melissoidesin L (4) were obtained from the aerial parts of Isodon melissoides (BENTHAM) H. HARA, their structures were established on the basis of the spectral methods, especially two dimensional (2D) NMR spectroscopy.

Four new ent-kaurane diterpenoids lushanrubescensins F-I (1-4), together with 11 known ones, lasiodonin (5), oridonin (6), ponicidin (7), isodonoiol (8), isodonal (9), rabdosin B (10), rabdoternins A and B (11 and 12), enmenol (13), epinodosin (14), and inflexusin (15), were isolated from Isodon rubescens var. lushanensis, and the structures were elucidated by spectroscopic analysis. The inhibitory effect against the K562, Bcap37, BGC823, BIU87, CA, CNE, and Hela cell lines of compounds 3 and 5-10 were evaluated.

A novel 20-nor-ent-kaurene diterpenoid, rubescensin N (1), and a new 7,20-epoxy-ent-kaurene diterpenoid, rubescensin O (2), along with the seven known diterpenoids rabdoternins A-F and xerophilusin N, were isolated from Isodon rubescens collected in Jiyuan prefecture, Henan Province, China. Their structures were established by extensive spectroscopic analysis. Compound 1 is the first example of a naturally occurring 20-nor-ent-kaurene diterpenoid from the Isodon genus plants.