160154-68-7

Upstream product

• 119646-68-3 3-bromo-5-tert-butyl-2-hydroxy-benzaldehyde 
• 17997-47-6 2-tri-n-butylstannylpyridine 
• 98-54-4 para-tert-butylphenol 
• 2725-53-3 2-hydroxy-5-t-butylbenzaldehyde 

Relevant academic research and scientific papers

Binucleating ligands: Synthesis of acyclic achiral and chiral Schiff base-pyridine and Schiff base-phosphine ligands

5-tert-Butyl-3-(2′-pyridyl)salicyaldehyde and 5-tert-butyl-3-(diphenylphosphino)salicyaldehyde were synthesized from 4-tert-butylphenol in good overall yields. Condensation of the salicyaldehydes with 2,3-diamino-2,3-dimethylbutane afforded the desired dinucleating Schiff base-pyridine and Schiff base-phosphine ligands, respectively. 5-tert-Butyl-3-(2′-pyridyl)salicyaldehyde reacted with optically active 1,2-diaminocyclohexanes to give chiral dinucleating Schiff base-pyridine ligands.

Mechanism and scope of salen bifunctional catalysts in asymmetric aldehyde and α-ketoester alkylation

Metal complexes of C2-symmetric Lewis acid/Lewis base salen ligands provide bifunctional activation resulting in rapid rates in the enantioselective addition of diethylzinc to aldehydes (up to 92% ee). Further experiments probed the reactivity of the individual Lewis acid and Lewis base components of the catalyst and established that both moieties are essential for asymmetric catalysis. These catalysts are also effective in the asymmetric addition of diethylzinc to α-ketoesters. This finding is significant because α-ketoesters alone serve as their own ligands to accelerate racemic 1,2-carbonyl addition of Et2Zn and racemic carbonyl reduction. The latter proceeds via a metalloene pathway, and often accounts for the predominant product. Singular Lewis acid catalysts do not accelerate enantioselective 1,2-addition over these two competing paths. The bifunctional amino salen catalysts, however, rapidly provide enantioenriched 1,2-addition products in excellent yield, complete chemoselectivity, and good enantioselectivity (up to 88% ee). A library of the bifunctional amino salens was synthesized and evaluated in this reaction. The utility of the α-ketoester method has been demonstrated in the synthesis of an opiate antagonist.

Synthesis of acyclic dinucleating Schiff base-pyridine and Schiff base-phosphine ligands

5-tert-butyl-3-pyridyl-salicyaldehyde and 5-tert-butyl-3-diphenylphosphino-salicyaldehyde have been synthesized from 4-tert-butylphenol in good overall yields. Condensation of the salicyaldehydes with 2,3-diamino-2,3-dimethylbutane afforded the desired dinucleating Schiff base-pyridine and Schiff base-phosphine ligands respectively.