Synthesis of (−)-halichonic acid and (−)-halichonic acid B

• Keith P. Reber and
• Emma L. Niner

Beilstein J. Org. Chem. 2022, 18, 1629–1635, doi:10.3762/bjoc.18.174

• using hydride reducing agents [13]. Nevertheless, specialized conditions for achieving C–N-bond cleavage of amides using SmI2 [13], Tf2O/Et3SiH [14], and stoichiometric Schwartz’s reagent [15] have been reported; however, none of these methods was successful in reducing amide 5 to the desired amine 4

Direct synthesis of anomeric tetrazolyl iminosugars from sugar-derived lactams

• Michał M. Więcław and
• Bartłomiej Furman

Beilstein J. Org. Chem. 2021, 17, 115–123, doi:10.3762/bjoc.17.12

• Schwartz’s reagent-mediated reductive amide functionalization followed by a variant of the Ugi–azide multicomponent reaction. The anomeric configurations of two products were unambiguously confirmed by X-ray analysis. This work also describes examples of interesting further transformations of the title

• products. Finally, some surprising observations regarding the mechanism of their formation were made. Keywords: amide functionalization; iminosugars; Schwartz’s reagent; tetrazole; Introduction The transformation of an amide into another chemical moiety in a controlled manner is not a trivial task

• hydride, known as Schwartz’s reagent [8]. This reduces the amide moiety, giving a complex that can be readily transformed into an imine or iminium cation [9]. It may perhaps be observed without straying too far afield from our primary focus that reduction of amides is actually not a leading use case of

Progress in the total synthesis of inthomycins

• Bidyut Kumar Senapati

Beilstein J. Org. Chem. 2021, 17, 58–82, doi:10.3762/bjoc.17.7

• reduction as reported previously [56]. Similarly, the treatment of (+)-83 with in situ-generated Schwartz’s reagent from zirconocene dichloride and DIBAL-H followed by iodine to produce an inseparable 6:1 mixture of (Z,E)-iododiene 85a and its 6-iodo-isomer 85b in 82% yield (Scheme 8). The vinyl iodide (Z,Z

Syntheses of spliceostatins and thailanstatins: a review

• William A. Donaldson

Beilstein J. Org. Chem. 2020, 16, 1991–2006, doi:10.3762/bjoc.16.166

• produced 46. The hydrozirconation of 46 with Schwartz’s reagent under equilibrating conditions, followed by the reaction with I2 gave the vinyl iodide 47. Finally, the activation of the C-14 hydroxy group and the SN2 displacement with azide gave the C-8–C-16 fragment 48. Ghosh relied on a reductive

Garner’s aldehyde as a versatile intermediate in the synthesis of enantiopure natural products

• Mikko Passiniemi and
• Ari M.P. Koskinen

Beilstein J. Org. Chem. 2013, 9, 2641–2659, doi:10.3762/bjoc.9.300

• hydrozirconation had to be done in CH2Cl2 due to the low solubility of the Schwartz’s reagent in toluene. After formation of the hydrozirconated species, the solvent could be changed to toluene. This reaction gave a slightly lower yield in toluene, but identical selectivity favouring adduct 60. By changing the

A reductive coupling strategy towards ripostatin A

• Kristin D. Schleicher and
• Timothy F. Jamison

Beilstein J. Org. Chem. 2013, 9, 1533–1550, doi:10.3762/bjoc.9.175

• of alkyne 50 with Schwartz’s reagent [54][55] was followed by transmetallation to zinc and nonselective addition into aldehyde 47. Oxidation of the resulting allylic alcohol mixture afforded the enone 53. Prior to the key oxy-Michael addition, it was necessary to remove the tert-butyldimethylsilyl

Alternaric acid: formal synthesis and related studies

• Michael C. Slade and
• Jeffrey S. Johnson

Beilstein J. Org. Chem. 2013, 9, 166–172, doi:10.3762/bjoc.9.19

• iodide 26 was generated by hydrozirconation/iodination of the free alkyne with Schwartz’s reagent [47]. The vinyl nucleophile 27 could be generated by Knochel’s Mg/I exchange [48] and employed successfully in the three-component-coupling reaction with silyl glyoxylate 1a and aldehyde 16ba to assemble 28

Homoallylic amines by reductive inter- and intramolecular coupling of allenes and nitriles

• Peter Wipf and
• Marija D. Manojlovic

Beilstein J. Org. Chem. 2011, 7, 824–830, doi:10.3762/bjoc.7.94

• addition of zirconocene hydrochloride (Cp2Zr(H)Cl, Schwartz’s reagent) to π-bonds usually leads predominantly to σ-complexes, and the resulting organozirconocene complexes are valuable reactive intermediates for the formation of carbon–halogen and carbon–carbon bonds [1][2][3][4][5][6]. The reaction of

• Schwartz’s reagent with allenes occurs at low temperature and provides a ready access to σ-bound allylzirconocenes [7]. These species can be added diastereoselectively to aldehydes and ketones to yield homoallylic alcohols, but they are generally not sufficiently reactive towards many other electrophiles [8

• allenes and nitriles, aiming to explore the in situ formation-addition of allylzirconocenes to N-zirconoimines (Scheme 1). Exposure of benzonitrile (7) and 3-methyl-1,2-butadiene (2) to an excess of Schwartz’s reagent in CH2Cl2 at −78 °C led to the formation of a bright red solution after gradual warming