Low-valent titanium mediated cleavage of trityl-O/N bonds in trityl ethers/amines via electron transfer process is reported. Chemoselective deprotection of trityl ethers in preference to benzyl ethers is achieved. The ease of cleavage of protected alcohols and amines is in the order O-allyl > O-trityl > O-benzyl; N-trityl > O-trityl bonds.
Heterolysis and homolysis energies for some carbon-oxygen bonds
作者:Edward M. Arnett、Kalyani Amarnath、Noel G. Harvey、Sampath Venimadhavan
DOI:10.1021/ja00176a039
日期:1990.9
Methods described previously for obtaining heterolysis (ΔH het ) and homolysis (ΔH homo ) enthalpies for bonds that can be cleaved to produce resonance-stabilized carbeniumions, anions, and radicals are extended to the study of carbon-oxygen bonds through the reactions of resonance-stabilized carbeniumions with substituted phenoxide ions. Titration calorimetry was used to obtain the heat of heterolysis
先前描述的获得异裂 (ΔH het ) 和均裂 (ΔH homo ) 焓的方法可以裂解以产生共振稳定的碳正离子、阴离子和自由基,通过共振反应扩展到碳-氧键的研究- 稳定的碳正离子与取代的酚盐离子。滴定量热法用于获得异解热,二次谐波交流伏安法(SHACV)法用于获得阴离子的可逆氧化电位