N-(1-Phenylethyl)aziridine-2-carboxylate esters in the synthesis of biologically relevant compounds

• Iwona E. Głowacka,
• Aleksandra Trocha,
• Andrzej E. Wróblewski and
• Dorota G. Piotrowska

Beilstein J. Org. Chem. 2019, 15, 1722–1757, doi:10.3762/bjoc.15.168

• and next (R)-118 were formed. The aziridine ring opening in (2S,1'R/S,1''R)-28 gave the acetate (1R/S,2S,1'R)-106 which was transformed into the 1,3-oxazolidin-2-one (4S,5R/S,1'R)-121 a precursor to (R)-118. Catalytic ruthenium tetroxide oxidation of (R)-118 followed by hydrolysis gave ᴅ-phenylalanine

Transient and intermediate carbocations in ruthenium tetroxide oxidation of saturated rings

• Manuel Pedrón,
• Laura Legnani,
• Maria-Assunta Chiacchio,
• Pierluigi Caramella,
• Tomás Tejero and
• Pedro Merino

Beilstein J. Org. Chem. 2019, 15, 1552–1562, doi:10.3762/bjoc.15.158

• carbocation. In the case of pyrrolidines, the carbocation is completely stabilized as an energy minimum in the form of an iminium ion and the reaction takes place in two steps. Keywords: alkanes; carbocations; DFT; oxidations; ruthenium tetroxide; Introduction Ruthenium-catalyzed oxidations [1][2] and, in

• particular, those involving ruthenium tetroxide [3][4] occupy a privileged position among the modern oxidation methods due to their versatility regarding functional groups that can be oxidized and formed [5]. Alkane functionalization continues to be a current challenge in organic synthesis [6] and oxidation

• with ruthenium tetroxide allows to introduce an oxygenated functionality (alcohol or carbonyl) into a saturated carbon skeleton [7]. Moreover, if oxygen or nitrogen atoms are present, the reaction leads to the formation of esters [8][9] or amides [10][11], respectively (Scheme 1). The reaction is

The direct oxidative diene cyclization and related reactions in natural product synthesis

• Juliane Adrian,
• Leona J. Gross and
• Christian B. W. Stark

Beilstein J. Org. Chem. 2016, 12, 2104–2123, doi:10.3762/bjoc.12.200

• functional theory calculations both by Strassner and co-workers (Mn(VII) and Os(VIII)) [12][13] and by Kirchner and co-workers (Ru(VIII)) [14]. Reasonable fractions of the trans-THF isomer can be produced using ruthenium tetroxide in specifically optimized solvent compositions [15] (for other means to obtain

• ][16][17]. In addition, for Ru(VIII) [17][18][19] and Mn(VII) [21] it has been shown that also 1,6-dienes serve as substrates and can thus be directly converted to tetrahydropyrans [20][21][22]; ruthenium tetroxide even oxidizes 1,7-dienes to oxepans [23]. However, it has to be noted that the latter

• succeeded in synthesizing cis-solamin A (29) utilizing a ruthenium tetroxide-catalyzed type A oxidative cyclization approach (Scheme 9) [80]. Silyl-protected dienediol 34, the oxidative cyclization precursor, was synthesized from all-trans-cyclododecatriene 33 in four steps including dihydroxylation, glycol

The difluoromethylene (CF₂) group in aliphatic chains: Synthesis and conformational preference of palmitic acids and nonadecane containing CF₂ groups

• Yi Wang,
• Ricardo Callejo,
• Alexandra M. Z. Slawin and
• David O’Hagan

Beilstein J. Org. Chem. 2014, 10, 18–25, doi:10.3762/bjoc.10.4

• ketones, to generate difluoromethyleneacetylenes, is methodology developed by Grée et al. [14][15][16][17][18] and it proved to be very reliable in our hands. An efficient hydrogenation generated the C-8 substituted difluoromethylenepentadecabenzene 12. Finally biphasic ruthenium tetroxide-catalyzed aryl

Mitomycins syntheses: a recent update

• Jean-Christophe Andrez

Beilstein J. Org. Chem. 2009, 5, No. 33, doi:10.3762/bjoc.5.33

Recent progress on the total synthesis of acetogenins from Annonaceae

• Nianguang Li,
• Zhihao Shi,
• Yuping Tang,
• Jianwei Chen and
• Xiang Li

Beilstein J. Org. Chem. 2008, 4, No. 48, doi:10.3762/bjoc.4.48

• oxidative cyclization of diol 84 with catalytic osmium tetroxide which gave the THF product 85 in high yield (Scheme 12). In 2006, Stark’s group [46] accomplished an enantioselective total synthesis of cis-solamin using a highly diastereoselective ruthenium tetroxide catalyzed oxidative cyclization as a

• crucial transformation (Scheme 13). In their synthetic route, commercially available (E,E,E)-1,5,9-cyclododecatriene 86 was readily converted into diene 87. Standard silyl protection of diol 87 afforded the cyclization precursor 88. Treatment of diene 88 under the ruthenium tetroxide catalyzed oxidative