The preparation of new functionalized [2.2]paracyclophane derivatives with N-containing functional groups

• Henning Hopf,
• Swaminathan Vijay Narayanan and
• Peter G. Jones

Beilstein J. Org. Chem. 2015, 11, 437–445, doi:10.3762/bjoc.11.50

• typical azide and carbonyl absorption bands in the vibrational spectral (see Supporting Information File 1 for complete spectroscopic data). The Curtius degradation of 27 provided the desired bis(isocyanate) 28 readily, though in a disappointing isolated yield of 30% only. Since the yield of the crude

Stereoselective synthesis of perillaldehyde-based chiral β-amino acid derivatives through conjugate addition of lithium amides

• Zsolt Szakonyi,
• Reijo Sillanpää and
• Ferenc Fülöp

Beilstein J. Org. Chem. 2014, 10, 2738–2742, doi:10.3762/bjoc.10.289

• achiral anhydrides followed by Curtius degradation [18][19][20]. The highly stereoselective Michael addition of lithium amide-type nucleophiles to α,β-unsaturated esters also proved to be a very efficient and useful method for the preparation of alicyclic β-amino acids in homochiral form [21][22

Scalable synthesis of (1-cyclopropyl)cyclopropylamine hydrochloride

• Sergei I. Kozhushkov,
• Alexander F. Khlebnikov,
• Rafael R. Kostikov,
• Dmitrii S. Yufit and
• Armin de Meijere

Beilstein J. Org. Chem. 2011, 7, 1003–1006, doi:10.3762/bjoc.7.113

• -cyclopropylcyclopropane (1) in 64% yield (89% on a 12.4 mmol scale), has been subjected to a Curtius degradation employing the Weinstock protocol to furnish the N-Boc-protected (1-cyclopropyl)cyclopropylamine 3 (76%). Deprotection of 3 with hydrogen chloride in diethyl ether gave the (1-cyclopropyl)cyclopropylamine

• hydrochloride (4·HCl) in 87% yield. Keywords: amines; building blocks; carboxylic acids; Curtius degradation; cyclopropanes; Introduction Several recent patent applications have stirred an increasing interest in research departments of pharmaceutical and agrochemical companies concerning 1- and 2-substituted

• conversion to the corresponding tert-butyl carbamate and subsequent column chromatography. Thus, this procedure was not easily scalable to 10–50 g quantities. To meet such demands, we have developed an alternative route to 4 from the easily available corresponding carboxylic acid 2 [17][18] by Curtius