通过NaBH4-TFA体系脱除芳基苄位羟基

1977年，Gribble及其伙伴报道了采用NaBH4-TFA体系还原二或者三取代芳基变为羟基物为相应的二或三取代芳基烷烃的方法，且收率较高。但是此种方法在运用到非苯位羟基或者单取代苄位羟基时，效果不理想。后来，经过一系列研究和优化之后，使得该方法可以运用到还原具有供电子基团，易形成碳正离子的苄位羟基,收率大致可以控制在>60%。

To a magnetically stirred suspension of start material (0.60 g, 3.1 mmol) and sodiumborohydrop powder (1.17 g, 30.9 mmol) in dry THF (25 mL) at 25°C was added TFA (15mL) over 30 min. After 1 h at 25℃, the mixture was carefully poured into 25% aqueous NaOH (30 mL) to basify (pH=11) and extracted with ether (2x30 mL). The combined extractswere dried (Na2SO4), filtered, and concentrated in vacu to afford an oil. flash chromatography (Hexanes) gave product (0.50 g, 91%) cleanly as a colorless oil.

Reference:Synth Commun.1990,20(4),487-493