A convenient enantioselective decarboxylative aldol reaction to access chiral α-hydroxy esters using β-keto acids

• Zhiqiang Duan,
• Jianlin Han,
• Ping Qian,
• Zirui Zhang,
• Yi Wang and
• Yi Pan

Beilstein J. Org. Chem. 2014, 10, 969–974, doi:10.3762/bjoc.10.95

• University, Nanjing, 210093, China 10.3762/bjoc.10.95 Abstract We show a convenient decarboxylative aldol process using a scandium catalyst and a PYBOX ligand to generate a series of highly functionalized chiral α-hydroxy esters. The protocol tolerates a broad range of β-keto acids with inactivated aromatic

• and aliphatic α-keto esters. The possible mechanism is rationalized. Keywords: enantioselective synthesis; hydroxy esters; scandium; Introduction The catalytic enantioselective construction of tertiary carbon centres is a major challenge in organic chemistry. The nucleophilic attack of carbonyls

• enolates. Though in the case of enzymatic reactions, decarboxylation occurs first to form the enolates, followed by condensation with esters; it is believed that in the scandium-catalysed aldol process of β-keto acid, similar to the case of malonic acid half thioesters, decarboxylation happens after the

Columnar/herringbone dual crystal packing of pyrenylsumanene and its photophysical properties

• Binod Babu Shrestha,
• Shuhei Higashibayashi and
• Hidehiro Sakurai

Beilstein J. Org. Chem. 2014, 10, 841–847, doi:10.3762/bjoc.10.80

• Pyrenylsumanene (1) was prepared from iodosumanene [8] and pyreneboronic acid in 84% yield through a Suzuki–Miyaura cross-coupling reaction (Scheme 1). The preparation of iodosumanene was improved by using a catalytic amount of scandium (III)triflate (Sc(OTf)3) with 6,6’-diiodo-2,2’-dimethoxy-1,1’-binaphthol (DIH

• , 0.378 mmol), 6,6’-diiodo-2,2’-dimethoxy-1,1’-binaphthol (DIH) (144 mg, 0.378 mmol) and scandium(III) triflate (9.3 mg, 0.0189 mmol) were placed in a 50 mL dry flask under an Ar atmosphere. Dry CH2Cl2 (37 mL) was then added. The reaction mixture was allowed to stir for 2.5 h at rt. The completion of

Synthesis of five- and six-membered cyclic organic peroxides: Key transformations into peroxide ring-retaining products

• Alexander O. Terent'ev,
• Dmitry A. Borisov,
• Vera A. Vil’ and
• Valery M. Dembitsky

Beilstein J. Org. Chem. 2014, 10, 34–114, doi:10.3762/bjoc.10.6

• the hydroperoxy acetals 229 under basic conditions. This method is suitable for the efficient synthesis of functionalized 1,2-dioxanes 230 in moderate to high yields (Scheme 65, Table 17). In early studies, scandium(III) triflate was used as the catalyst for the hydroperoxidation of ketones with the

Fifty years of oxacalix[3]arenes: A review

• Kevin Cottet,
• Paula M. Marcos and
• Peter J. Cragg

Beilstein J. Org. Chem. 2012, 8, 201–226, doi:10.3762/bjoc.8.22

• reported the crystal structure and dynamic behaviour of a scandium(III) complex of 3a [59]. Later, the X-ray structures of lanthanum, lutetium and yttrium complexes with the same macrocycle showed 2:2 complexes between the cations and macrocycles [60]. In these structures the lanthanides are either six

Gold-catalyzed propargylic substitutions: Scope and synthetic developments

• Olivier Debleds,
• Eric Gayon,
• Emmanuel Vrancken and
• Jean-Marc Campagne

Beilstein J. Org. Chem. 2011, 7, 866–877, doi:10.3762/bjoc.7.99

• Friedel–Crafts type reactions with benzylic and propargylic alcohols. Shortly after, Sanz and Zhan discovered, that these reactions could also be carried out under Brønsted acid and FeCl3 catalysis, respectively [26][27][28][29]. Later, the use of copper, indium, bismuth, scandium, ytterbium

A review of new developments in the Friedel–Crafts alkylation – From green chemistry to asymmetric catalysis

• Magnus Rueping and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2010, 6, No. 6, doi:10.3762/bjoc.6.6

• scandium-catalyzed FC alkylation using 3-sulfanyl- and 3-selanylpropargylic alcohols 101. With 5 mol% of Sc(OTf)3 as the catalyst and a surprisingly low reaction temperature (0 °C) the desired propargylated arenes 102 were isolated in good to high yields. Beside arenes and heteroarenes, allylsilane and

• synthesis of podophyllotoxin, mimosifoliol and O-methyldetrol. Scandium-catalyzed arylation of 3-sulfanyl- and 3-selanylpropargyl alcohols. Synthesis of 1,3-diarylpropynes via direct coupling of propargyl trichloracetimidates and arenes. Diastereoselective substitutions of benzyl alcohols. (A) First

An efficient synthesis of novel pyrano[2,3-d]- and furopyrano[2,3-d]pyrimidines via indium- catalyzed multi- component domino reaction

• Dipak Prajapati and
• Mukut Gohain

Beilstein J. Org. Chem. 2006, 2, No. 11, doi:10.1186/1860-5397-2-11

• scandium or ytterbium triflate was used as catalyst but indium chloride gives better results (Table 1). In a control experiment, the reaction also proceeded without the use of any catalysts, but it yields the compound 5 in a (1:1) mixture of diastereomers in 65–70% yields (Table 1). To further investigate