Phase-Transfer-CatalysedN-Alkylation ofN-Substituted Formamides; An Alternative Procedure for the Ritter Reaction

Beyond alkyl transfer: Synthesis of main group metal (Mg, Ca, Zn) silyl and tris(oxazolinyl)borato complexes and their stoichiometric and catalytic reactions with borane Lewis acids and carbonyls

“…The Ca−Si distances of 3.126(2) and 3.146(2) Å are inequivalent; however, the Ca1−N distances (mean Ca-N distance, 2.521 ± 0.005 Å) are equivalent within 3 error. The Ca−Si interatomic distances are slightly longer than the corresponding distances in the five-coordinate Ca{Si(SiMe 3 ) 3 } 2 THF 3 (3.0421(9) and 3.0861(9) Å), 37 which is likely related to the Ca center's increased coordination number, and slightly shorter than the corresponding distances in the sixcoordinate Ca{SiPh 3 } 2 THF 4 (3.1503(8) Å). 38 The H atoms belonging to the β-Si atoms were found objectively on a difference Fourier map and refined isotropically.…”

“…Furthermore, 1 H NMR spectra of mixtures of the esters and silanes studied in Table 1 with 10 mol % B(C 6 F 5 ) 3 contained signals corresponding to several unidentified species as the major products likely resulting from ester cleavage, 37 and the signals assigned to the corresponding hydrosilylation products were minor (although the amounts varied between primary, secondary, and tertiary silanes). Thus, the catalytic hydrosilylation is not mediated by trace contamination of B(C 6 F 5 ) 3 .…”

Synthesis and Crystal Structure of Unexpected (1S,4R,5R,6S)-4-Cyano-2,2,6-trimethyl-3-azabicyclo[3.3.1]nonan-6-yl Acetate

“…[1] The resulting N-alkylformamides from these methods can be hydrolysed comparatively easily, thereby providing an important synthetic route to the corresponding N-alkylamine. [10] Unfortunately, these 1-substituted nitriles of piperidines [12], [13] and has helped propose the suggested mechanism for the reaction below. X-ray analysis of the recrystallized product unequivocally confirm the structure of compound 5.…”

6.07 Ritter-Type Reactions

“…Although the usual Ritter procedure yields a primary amine, alkylation of the alkylformamide NH group before hydrolysis also affords a convenient route to secondary amines. 28 A limitation of the amine preparation is that acetamides (and many other amides) frequently require surprisingly savage basic hydrolysis conditions, whereas acidic hydrolysis often results in loss of the alkyl group. These conditions are contrasted here (Scheme 9) by the conversion of alkene 20 into N-tert-octylamine 21 using both the formamide 22 and acetamide 23 pathways.…”

“…Many other polycyclic bridgehead amines exhibit related biological properties and the Ritter approach has been widely exploited in their synthesis. Equation 28 shows one recent example using more modern methods. Ritter reaction of the noradamantyl diol 50 is combined with rearrangement to the adamantyl product 51.…”