Highly efficient synthesis of spirocyclic (1R)-camphor-derived triazolium salts: application in the catalytic asymmetric benzoin condensation

Organocatalytic Reactions Enabled by N-Heterocyclic Carbenes

“…As a result of the success of this reaction, it has become a benchmark reaction for the application of new NHC manifolds, and several groups continue to evaluate new scaffolds in this way (Scheme 16). 55 …”

Synthesis and Application of 1,2-Aminoalcohols with Neoisopulegol-Based Octahydrobenzofuran Core

“…1,2-aminoalcohols have also been demonstrated to be excellent chiral auxiliaries and chiral catalysts in asymmetric synthesis [33]. To achieve new, efficient, and commercially available chiral catalysts, natural chiral terpenes, such as α-pinene [34][35][36][37][38], β-pinene [34,39], (-)-3-carene [39,40], (-)verbenone [41,42], (-)-fenchone [43,44], (+)-camphor [43,45,46], and (-)-menthone [47] have proven to be excellent sources for the synthesis of bifunctional chiral compounds and heterocycles.…”

“…1,2-aminoalcohols have also been demonstrated to be excellent chiral auxiliaries and chiral catalysts in asymmetric synthesis [33]. To achieve new, efficient, and commercially available chiral catalysts, natural chiral terpenes, such as α-pinene [34-38], β-pinene [34,39], (-)-3-carene [39,40], (-)-verbenone [41,42], (-)-fenchone [43,44], (+)-camphor [43,45,46], and (-)-menthone [47] have proven to be excellent sources for the synthesis of bifunctional chiral compounds and heterocycles.In the present work, we set out to create a compound library with a (+)-neoisopulegol-based octahydrobenzofuran core and 1,2-aminoalcohol moieties. The synthesis started from commercially available (-)-isopulegol and then utilizing the resulting 1,2-aminoalcohol derivatives as chiral catalysts in the enantioselective addition of diethylzinc to benzaldehyde.…”

Synthesis of 4′-alkyl-8-azaspiro[bicyclo[3.2.1]octane-3,2′-morpholin]-5′-ones

“…Known procedures for the synthesis of morpholinones spiro-fused to tetrahydronaphthalene [19], benzopyran [20], and bicyclo[2.2.1]heptane fragments [21] are based on a series of transformations of the corresponding cyclic ketones, and they include trimethylsilylcyanation of the ketone group, reduction to β-amino alcohol, and closure of 1,4-oxazine ring by the action of chloroacetyl chloride. To obtain spiro morpholinones substituted at the nitrogen atom, an additional N-alkylation step is necessary [20].…”

“…), δ C , ppm: 6.91 (2C, CH 2 ), 27.27 (CH 2 ), 27.99 (CH 2 ), 28 21. [C(CH 3 ) 3 ], 30.01 (CH), 40.52 (CH 2 ), 41.29 (CH 2 ), 51.63 (CH), 52.49 (CH), 62.11 (CH 2 ), 68.76 (C spiro ), 78.69 [C(CH 3 ) 3 ], 153.08 (C=O).…”