Stereoselective synthesis and transformation of pinane-based 2-amino-1,3-diols

• Ákos Bajtel,
• Mounir Raji,
• Matti Haukka,
• Ferenc Fülöp and
• Zsolt Szakonyi

Beilstein J. Org. Chem. 2021, 17, 983–990, doi:10.3762/bjoc.17.80

• NMR and X-ray spectroscopic techniques. The regioisomeric spiro-oxazolidin-2-one was prepared in a similar way starting from the commercially available (1R)-(−)-myrtenol (10). The reduction or alkaline hydrolysis of the oxazolidines, followed by reductive alkylation resulted in primary and secondary 2

Diosgenyl 2-amino-2-deoxy-β-D-galactopyranoside: synthesis, derivatives and antimicrobial activity

• Henryk Myszka,
• Patrycja Sokołowska,
• Agnieszka Cieślińska,
• Andrzej Nowacki,
• Maciej Jaśkiewicz,
• Wojciech Kamysz and
• Beata Liberek

Beilstein J. Org. Chem. 2017, 13, 2310–2315, doi:10.3762/bjoc.13.227

• Supporting Information File 1 for experimental and NMR data). To obtain the N-alkyl derivatives of 4, a method called “two-step reductive alkylation of amines” was chosen. This method was successfully used to prepare N-alkyl derivatives of other amino sugars, including diosgenyl aminoglucosides [34][35]. The

• presented reductive alkylation consists of a reaction of amine 4 with the appropriate aldehyde, which results in the respective imine subsequently reduced with sodium cyanoborohydride to the alkylated amine. Thus, the reaction of 4 with 1.5 molar excess of acetaldehyde followed by the in situ reduction with

Accessing simply-substituted 4-hydroxytetrahydroisoquinolines via Pomeranz–Fritsch–Bobbitt reaction with non-activated and moderately-activated systems

• Marco Mottinelli,
• Mathew P. Leese and
• Barry V. L. Potter

Beilstein J. Org. Chem. 2017, 13, 1871–1878, doi:10.3762/bjoc.13.182

• , is scarcely represented in the literature. Here, the factors controlling the regiochemical outcome of cyclization are evaluated. Results: A double reductive alkylation was telescoped into a one-pot reaction delivering good to excellent yields of desired aminoacetals for cyclization. Cyclization of

• aforementioned aims, we envisaged that the synthesis set out in Scheme 2 could deliver access to substrates for the PFB reaction such as 9. After an initial, unfruitful, attempt to obtain the aminoacetals 9 from sequential condensation of aniline and alkyl and aryl halides, a double reductive alkylation that

• reductive alkylation. Screening of the acidic catalyst for the PFB reaction. Ratio between the formation of 10d,f,i,j,k and 15d,f,i,j,k at different reaction concentrations. Supporting Information Supporting Information File 214: Synthetic and purification methodologies and spectroscopic data

One-pot synthesis of 4′-alkyl-4-cyanobiaryls on the basis of the terephthalonitrile dianion and neutral aromatic nitrile cross-coupling

• Roman Yu. Peshkov,
• Elena V. Panteleeva,
• Wang Chunyan,
• Evgeny V. Tretyakov and
• Vitalij D. Shteingarts

Beilstein J. Org. Chem. 2016, 12, 1577–1584, doi:10.3762/bjoc.12.153

• -coupling; cyanoarenes; reactive intermediates; reductive alkylation; Introduction Alkylcyanobiphenyls are well known largely due to their mesogenic properties, which were discovered by Gray in the 1970th [1][2]. Alkylcyanobiphenyls and their analogs (e.g., dialkyl and alkoxy alkyl derivatives) are still

N-Alkyl derivatives of diosgenyl 2-amino-2-deoxy-β-D-glucopyranoside; synthesis and antimicrobial activity

• Agata Walczewska,
• Daria Grzywacz,
• Dorota Bednarczyk,
• Małgorzata Dawgul,
• Andrzej Nowacki,
• Wojciech Kamysz,
• Beata Liberek and
• Henryk Myszka

Beilstein J. Org. Chem. 2015, 11, 869–874, doi:10.3762/bjoc.11.97

• -β-D-glucopyranose (7) was obtained by complete deprotections of 6a–d, as previously reported [45]. To obtain N-alkyl derivatives of diosgenyl 2-amino-2-deoxy-β-D-glucopyranoside (7), a method called “reductive alkylation of amines” was chosen. This method was previously successfully used to prepare

• N-alkyl derivatives of 1,3,4,6-tetra-O-acetyl-2-amino-2-deoxy-D-glucose [51][52]. Thus, reductive alkylation of 7 with a 1.2 molar excess of the appropriate aldehyde and a twofold molar excess of NaBH3CN provided mono- (9, 11, 15, 16) and dialkylated products (8, 10, 12–14, 17), solely or as

Synthesis and optical properties of pyrrolidinyl peptide nucleic acid carrying a clicked Nile red label

• Nattawut Yotapan,
• Chayan Charoenpakdee,
• Pawinee Wathanathavorn,
• Boonsong Ditmangklo,
• Hans-Achim Wagenknecht and
• Tirayut Vilaivan

Beilstein J. Org. Chem. 2014, 10, 2166–2174, doi:10.3762/bjoc.10.224

• a reductive alkylation strategy previously reported by our group (Scheme 2) [31]. Two lysine residues were incorporated at the N- and C-termini of the acpcPNA to ensure a sufficient solubility in aqueous solution. Five acpcPNA sequences, each of which singly labeled at the backbone with Nile red

Automated solid-phase peptide synthesis to obtain therapeutic peptides

• Veronika Mäde,
• Sylvia Els-Heindl and
• Annette G. Beck-Sickinger

Beilstein J. Org. Chem. 2014, 10, 1197–1212, doi:10.3762/bjoc.10.118

• PEGylation was performed at the N-terminus with 5, 10 and 20 kDa methoxy PEG-aldehydes by reductive alkylation. With this strategy, they could circumvent unspecific multi-PEGylation by maintaining the reduced immunoreactivity, which is important for hepatitis therapy [117]. As PEG has some limitations as

Towards stereochemical control: A short formal enantioselective total synthesis of pumiliotoxins 251D and 237A

• Jie Zhang,
• Hong-Kui Zhang and
• Pei-Qiang Huang

Beilstein J. Org. Chem. 2013, 9, 2358–2366, doi:10.3762/bjoc.9.271

• -hydroxyglutarimide-based regio- and trans-diastereoselective reductive alkylation, a synthetic methodology developed from our laboratory [32][38][45][46], as the starting point. Our synthesis started from the addition of a freshly prepared 3-butenylmagnesium bromide to imide 13 [47] in dichloromethane at −78 °C for

The chemistry of isoindole natural products

• Klaus Speck and
• Thomas Magauer

Beilstein J. Org. Chem. 2013, 9, 2048–2078, doi:10.3762/bjoc.9.243

• isoindolinone 174, which was converted to bromide 175. Reductive alkylation of the protected Wieland–Miescher ketone 176 with bromide 175 using Birch conditions gave 177 as a single diastereoisomer. Epoxide 178 could be prepared in seven steps from 177, but was obtained as a mixture of inseparable

Tandem aldehyde–alkyne–amine coupling/cycloisomerization: A new synthesis of coumarins

• Maddi Sridhar Reddy,
• Nuligonda Thirupathi and
• Madala Haribabu

Beilstein J. Org. Chem. 2013, 9, 180–184, doi:10.3762/bjoc.9.21

• in equivalence of reductive alkylation of amines while at the same time appending an alkyne, i.e., a highly useful moiety for further functionlization. This three-component coupling has been accomplished with a very broad range of transition metals, including copper, silver, gold, ruthenium/copper

Alkenes from β-lithiooxyphosphonium ylides generated by trapping α-lithiated terminal epoxides with triphenylphosphine

• David. M. Hodgson and
• Rosanne S. D. Persaud

Beilstein J. Org. Chem. 2012, 8, 1896–1900, doi:10.3762/bjoc.8.219

• referred to as reductive alkylation [41]. Also, while PPh3 is itself capable of being lithiated–carboxylated (at a meta-position, 6% yield) by using BuLi in Et2O [42], this requires significantly higher temperatures (reflux, 46 h) than those applied here. In the event, the use of either s-BuLi or t-BuLi

• with epoxide 11 in the presence of Ph3P in a variety of solvents (THF, Et2O, t-BuOMe, toluene) followed by the addition of benzaldehyde was found to give allylic alcohol 7, albeit in low yields with reductive alkylation always being the dominant reaction pathway, and typically ~30% of epoxide 11 and