Chemoselectivity in the Reduction of (2S,4S)‐4‐Amino‐5‐oxoproline Derivatives with Borane Complexes

Abstract

Reduction of the carbonyl groups in N‐protected (2S,4S)‐4‐amino‐5‐oxo‐1‐phenylprolinates with BH3 complexes resulted in (2S,4S)‐4‐aminoproline or (2S,4S)‐4‐aminoprolinol derivatives depending on the reaction conditions and the type of protecting groups used.

Branching out: redox strategies towards the synthesis of acyclic α-tertiary ethers

“…410,411 In a similar manner, borane reductions of amides are often associated with ether side products if esters are also present. 412 Alternative strategies have sought to isolate the transiently formed mixed acetals as silyl-protected or acetyl-activated hemiacetals, which can be further reduced to the desired ethers (Scheme 108C). 413,414 More recently, the application of transition-metal catalysed hydrosilylation has shown significant potential in selective ester reductions.…”

“…410,411 In a similar manner, borane reductions of amides are often associated with ether side products if esters are also present. 412…”

Enantioselective Reduction of Prochiral Ketones with NaBH4/Me2SO4/(S)-Me-CBS

“…[1] It has been widely used in the hydroboration of unsaturated C-C bonds, [2] and reduction of carbonyl compounds, [3] oximes, [4] imines, [5] and amide. [6] One of the most important applications of borane is reducing prochiral ketones to the corresponding enantioenriched second aryl alcohols in the presence of chiral catalyst. [7] Enantiomerically pure secondary alcohols are important building blocks for the synthesis of various other organic compounds such as halides, esters, ethers, ketones, amines, and many biologically active compounds.…”