Recent applications of porphyrins as photocatalysts in organic synthesis: batch and continuous flow approaches

• Rodrigo Costa e Silva,
• Luely Oliveira da Silva,
• Aloisio de Andrade Bartolomeu,
• Timothy John Brocksom and
• Kleber Thiago de Oliveira

Beilstein J. Org. Chem. 2020, 16, 917–955, doi:10.3762/bjoc.16.83

• enantioselective and chemoselective oxidations of many organic compounds. Notably, the Gryko’s group recently described an enantio- and diastereoselective approach involving a porphyrin-based photooxygenation of aldehydes with sequential reduction to yield chiral diols in yields up to 91% and significant er (up to

Asymmetric synthesis of CF₂-functionalized aziridines by combined strong Brønsted acid catalysis

• Xing-Fa Tan,
• Fa-Guang Zhang and
• Jun-An Ma

Beilstein J. Org. Chem. 2020, 16, 638–644, doi:10.3762/bjoc.16.60

• no enantioselectivity at all. As arylboronic acids have been harnessed to enhance the Brønsted acidity in asymmetric organocatalysis in combination with chiral diols or chiral aminoalcohols [40][41][42][43][44], we envisioned that the simultaneous use of arylboronic acids and chiral Brønsted acids

Synthesis of a sucrose dimer with enone tether; a study on its functionalization

• Zbigniew Pakulski,
• Norbert Gajda,
• Magdalena Jawiczuk,
• Jadwiga Frelek,
• Piotr Cmoch and
• Sławomir Jarosz

Beilstein J. Org. Chem. 2014, 10, 1246–1254, doi:10.3762/bjoc.10.124

• -715 spectropolarimeter and were collected at 0.5 nm/step with an integration time of 0.25 s over the range 235–800 nm with 200 nm/min scan speed, 5 scans. For the ECD standard measurements the chiral diols (~3.6 mg, ca. 0.003 M) was mixed with stock complex [Mo2(O2CCH3)4] (Mo1) (~0.9 mg, ca. 0.002 M

Development of the titanium–TADDOLate-catalyzed asymmetric fluorination of β-ketoesters

• Lukas Hintermann,
• Mauro Perseghini and
• Antonio Togni

Beilstein J. Org. Chem. 2011, 7, 1421–1435, doi:10.3762/bjoc.7.166

• prepared in situ from Me2AlCl and several chiral diols, were not catalytically active. However, the well-established Lewis acid [(R,R-TADDOLato)TiCl2] [82] (Scheme 1) displayed good catalytic activity (5 mol %, 1→1-F in 4 h) and gave (S)-1-F with an enantiomeric excess of 28% (for a complex incorporating

• 6), the reagents induced similar enantioselectivity. Ligand variations in the asymmetric titanium-catalyzed fluorination reaction We tested several chiral diols in the titanium-catalyzed asymmetric fluorination, but notable success was only achieved with TADDOL ligands [91]. We obtained several

Directed ortho,ortho'-dimetalation of hydrobenzoin: Rapid access to hydrobenzoin derivatives useful for asymmetric synthesis

• Inhee Cho,
• Labros Meimetis,
• Lee Belding,
• Michael J. Katz,
• Travis Dudding and
• Robert Britton

Beilstein J. Org. Chem. 2011, 7, 1315–1322, doi:10.3762/bjoc.7.154

• groups. The optimization and scope of this reaction are discussed, and the utility of this process is demonstrated in the one-pot preparation of a number of chiral diols as well as a short synthesis of the chiral ligand Vivol. Keywords: chiral diol; directed ortho-metalation; hydrobenzoin; Introduction

• . Importantly, a wide variety of chiral diols (e.g., Vivol (4)) are now readily accessible in optically pure form following this one-pot reaction. Although the range of electrophiles that engage in synthetically useful reactions with the tetralithio intermediate 8 is limited, the diiodohydrobenzoin 12 and bis

• (benzoxaborol) 20 are both prepared in good yield and are readily derivatized through cross-coupling reactions. We are currently exploring the utility of the bis(benzoxaborol) 20 and derivatives of this substance as chiral Lewis acids and will report our findings in due course. Chiral diols useful for

Control of asymmetric biaryl conformations with terpenol moieties: Syntheses, structures and energetics of new enantiopure C₂-symmetric diols

• Y. Alpagut,
• B. Goldfuss and
• J.-M. Neudörfl

Beilstein J. Org. Chem. 2008, 4, No. 25, doi:10.3762/bjoc.4.25

• : chiral diols; hydrogen bonds; axial chirality; terpenes; Introduction Enantiopure biaryl systems with flexible chiral axes are widespread, e.g. in pharmacological natural products or as ligands in enantioselective catalyses [1]. Chelating C2-symmetric diols such as BINOLs [2][3][4] and TADDOLs [5][6