Synthesis of 1,3-aminonaphthols by diastereoselective Betti-type aminoalkylation of dihydroxy naphthalenes; diastereoselectivity, absolute configuration, and application

Recent advances in the synthesis and synthetic applications of Betti base (aminoalkylnaphthol) and bis-Betti base derivatives

“…The major diastereomers (90-96%) formed could be isolated in pure form. 73 These chiral aminonaphthols have been used as precatalysts for the addition of diethylzinc and alkynylzinc reagents to aldehydes in toluene at room temperature with enantioselectivities of up to 98% and 50% ee, respectively. Ganesan et al 74 Sulfanilic acid-functionalized silica-coated nano-Fe 3 O 4 particles (MNPs-PhSO 3 H) as an efficient, reusable and magnetically separable catalyst has been studied for the solventfree synthesis of 1-aminoalkyl-2-naphthols 108 at 120 C. Treatment of a variety of aldehydes and 2-naphthol with heterocyclic amines afforded the corresponding 1-aminoalky-2naphthol derivatives in 81-92% yields aer 10-20 min (Scheme 67).…”

“…121 Bis-Betti bases 161 and 162 have been synthesized diastereoselectively by applying a solvent-free 'Betti-type' condensation using 2,6-dihydroxynaphthalene, (S)-phenylethylamine, and mmethylbenzaldehyde or 1-naphthaldehyde at 80 C for 48 h. The major diastereomers formed could be isolated in pure form (Scheme 113). 73 A mild, efficient and straightforward method has been developed for the synthesis of bis-Betti bases 163 via a pseudo-vecomponent, one-pot condensation reaction of heteroarylamines, terephthaldehyde and naphthols in the presence of formic acid as catalyst at 80 C within 5-20 min under solvent-free conditions (Scheme 114). A wide range of heteroarylamines with electrondonating and electron-withdrawing groups and naphthols were well tolerated under the reaction conditions and afforded products in 85-92% yields.…”

New Advances in the Synthetic Application of Enantiomeric 1-Phenylethylamine (α-PEA): Privileged Chiral Inducer and Auxiliary

“…All the ligands with (S)-α-PEA fragments gave the R isomer of the product with good yield and enantioselectivity [73]. A series of chiral 1,3-aminonaphthols was synthesized using a Betti-type reaction between monoor dihydroxy naphthalenes, aldehydes, and (S)-α-PEA [73]. Thus, the obtained modular ligands were applied in the enantioselective addition of Et 2 Zn and alkynyl-Zn to ferrocencarbaldehyde (Scheme 49).…”

Synthesis and application of novel 1,2,3‐triazolylferrocene‐containing ionic liquid supported on Fe3O4 nanocatalyst in the synthesis of new pyran‐substituted Betti bases

“…[17][18][19][20] One of the important multicomponent reactions is the Betti reaction which was introduced by Mario Betti. [21,22] After the initial report of the synthesis of Betti bases, the study of these compounds has become an important area, [23][24][25][26] because of their significant biological, [27,28] synthetic [29][30][31][32] and catalytic [33] applications.…”