Pyridine C(sp²)–H bond functionalization under transition-metal and rare earth metal catalysis

• Haritha Sindhe,
• Malladi Mounika Reddy,
• Karthikeyan Rajkumar,
• Akshay Kamble,
• Amardeep Singh,
• Anand Kumar and
• Satyasheel Sharma

Beilstein J. Org. Chem. 2023, 19, 820–863, doi:10.3762/bjoc.19.62

A permutation approach to the assignment of the configuration to diastereomeric tetrads by comparison of experimental and ab initio calculated differences in NMR data

• Przemysław J. Boratyński

Beilstein J. Org. Chem. 2017, 13, 2478–2485, doi:10.3762/bjoc.13.245

• . Keywords: GIAO; NMR; stereochemistry assignment; Introduction In a stereodivergent synthesis [1] often two or more new stereocenters are created with or without control of stereochemistry and it is necessary to identify the configuration of the products. Any diastereomers exhibit disparate NMR spectra

Modular synthesis of the pyrimidine core of the manzacidins by divergent Tsuji–Trost coupling

• Sebastian Bretzke,
• Stephan Scheeff,
• Felicitas Vollmeyer,
• Friederike Eberhagen,
• Frank Rominger and
• Dirk Menche

Beilstein J. Org. Chem. 2016, 12, 1111–1121, doi:10.3762/bjoc.12.107

• urea-type cyclization precursor 19. Stereodivergent synthesis of 1,3-syn- and anti-tetrahydropyrimidinones [31]. Stereoselective synthesis of all possible stereoisomers of the manzacidin core amine by asymmetric addition to chiral tert-butanesulfinyl ketimines. Synthesis of the authentic cyclization

First chemoenzymatic stereodivergent synthesis of both enantiomers of promethazine and ethopropazine

• Paweł Borowiecki,
• Daniel Paprocki and
• Maciej Dranka

Beilstein J. Org. Chem. 2014, 10, 3038–3055, doi:10.3762/bjoc.10.322

• columns. Keywords: ethopropazine; lipase-catalyzed kinetic resolution; Mosher methodology; promethazine; stereodivergent synthesis; Introduction Since enantiomorphs of biologically active compounds exhibit significant differences in their pharmacokinetic and pharmacodynamic behavior, optical purity of

• charge (δ+) is obviously better stabilized than at the neighboring carbon atom. This clearly suggests that electrostatic factors (interactions) are favored over steric hindrance effects giving the opportunity of a purely solvent-dependent stereodivergent synthesis of therapeutically active ingredients 9

Concise, stereodivergent and highly stereoselective synthesis of cis- and trans-2-substituted 3-hydroxypiperidines – development of a phosphite-driven cyclodehydration

• Peter H. Huy,
• Julia C. Westphal and
• Ari M. P. Koskinen

Beilstein J. Org. Chem. 2014, 10, 369–383, doi:10.3762/bjoc.10.35

• pharmacological activities of compounds based on the 3-piperidinol scaffold, a step-economic, scalable and stereodivergent synthesis of both cis- and trans-diastereomers of B in good diastereoselectivities is highly desirable. In the syntheses of potentially new drug candidates scalability is a significant factor

• the step-economic and stereodivergent synthesis of trans- and cis-2-substituted 3-piperidinols B, we want to report the development of this sequence in more detail with a focus on the phosphite-mediated cyclodehydration. Additionally, the synthesis of a side chain functionalized piperidinol derived

Multigramme synthesis and asymmetric dihydroxylation of a 4-fluorobut-2E-enoate

• James A. B. Laurenson,
• John A. Parkinson,
• Jonathan M. Percy,
• Giuseppe Rinaudo and
• Ricard Roig

Beilstein J. Org. Chem. 2013, 9, 2660–2668, doi:10.3762/bjoc.9.301

• /deprotection chemistry, and in some cases, the availability of the precursor sugar. Some less common sugars are expensive and available in limited quantities. The alternative approach involves de novo stereodivergent synthesis, which elaborates small fluorinated building blocks using the reactions of modern

Stereodivergent synthesis of jaspine B and its isomers using a carbohydrate-derived alkoxyallene as C₃-building block

• Volker M. Schmiedel,
• Stefano Stefani and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2013, 9, 2564–2569, doi:10.3762/bjoc.9.291

• auxiliaries for the synthesis of enantiopure natural products such as preussin [39] and anisomycin [40] or in hetero Diels–Alder reactions [41][42]. For the stereodivergent synthesis of both enantiomers of jaspine B (1), we chose diacetoneglucose-derived alkoxyallene 11, which is easily accessible on gram

• material (Scheme 9). Conclusion We developed a stereodivergent synthesis of enantiopure jaspine B and three of its stereoisomers. Important knowledge could also be gained during the preparation of the racemic compounds. The carbohydrate-derived alkoxyallene 11 proved to be useful as a chiral C3-building

Addition of lithiated enol ethers to nitrones and subsequent Lewis acid induced cyclizations to enantiopure 3,6-dihydro-2H-pyrans – an approach to carbohydrate mimetics

• Fabian Pfrengle and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2010, 6, No. 75, doi:10.3762/bjoc.6.75

• Fabian Pfrengle Hans-Ulrich Reissig Freie Universität Berlin, Institut für Chemie und Biochemie, Takustrasse 3, D-14195 Berlin, Germany 10.3762/bjoc.6.75 Abstract A stereodivergent synthesis of enantiopure 3,6-dihydro-2H-pyrans is presented. The addition of lithiated enol ethers to carbohydrate

• to a tricarboxylic acid core. Keywords: aminopyrans; carbohydrate mimetics; Lewis acids; lithiated enol ethers; nitrones; oxidative cleavage; stereodivergent synthesis; Introduction The pyran structural motif can be found in numerous bioactive natural products. Possible strategies towards their