A Practical Synthesis of <scp>l</scp>-Valyl-pyrrolidine-(2<i>R</i>)-boronic Acid: Efficient Recycling of the Costly Chiral Auxiliary (+)-Pinanediol
作者:Frank S. Gibson、Ambarish K. Singh、Maxime C. Soumeillant、Percy S. Manchand、Michael Humora、David R. Kronenthal
DOI:10.1021/op025587b
日期:2002.11.1
A practical synthesis Of L-valyl-pyrrolidine-(2R)-boronic acid (1) is detailed. A previously disclosed synthesis of 1 (Snow, R.; Kelly, T. R.; Adams, J.; Coutts, S.; Perry, C. (Boehringer Ingelheirn Pharmaceuticals, Inc.). WO 93/10127, 1993) was significantly improved by developing an efficient process for recycling the costly chiral auxiliary (+)- pinanediol.
A (−)-Sparteine-Directed Highly Enantioselective Synthesis of Boroproline. Solid- and Solution-State Structure and Properties
作者:Andrei S. Batsanov、Christophe Grosjean、Thorben Schütz、Andrew Whiting
DOI:10.1021/jo0708792
日期:2007.8.1
A two-step, direct asymmetric synthesis of the trifluoroacetate ammonium salt of boroproline is reported. (−)-Sparteine-mediatedlithiation of N-Boc-pyrrolidine afforded N-Boc-aminoboronic acid in good yield and enantioselectivity as determined by HPLC (pinanediol ester). Deprotection using TFA yielded the ammonium salt; full characterization data are presented, and the structure in aqueous solution