Premium
Visible Light‐Mediated Synthesis of Enantiopure γ‐Cyclobutane Amino and 3‐(Aminomethyl)‐5‐phenylpentanoic Acids
Author(s) -
Kerres Sabine,
Plut Eva,
Malcherek Simon,
Rehbein Julia,
Reiser Oliver
Publication year - 2019
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201801413
Subject(s) - chemistry , enantiopure drug , cyclobutane , enantiomer , bicyclic molecule , stereochemistry , amide , enantioselective synthesis , organic chemistry , catalysis , ring (chemistry)
A visible light‐mediated [2+2] photocycloaddition of amide‐linked dienes using [Ir(dtb‐bpy)(dF(CF 3 )ppy) 2 ]PF 6 as triplet sensitizer was applied to generate a variety of N ‐ tert ‐butyl, N ‐benzyl‐ and N ‐ tert ‐butoxycarbonyl‐protected 3‐azabicyclo[3.2.0]heptan‐2‐ones in good yields and with good diastereoselectivity. Density functional theory calculations shed light on the conformational prerequisites for the [2+2] photocycloaddition. The bicyclic key structures could be readily transformed into γ‐cyclobutane amino acids. For the obtained racemic 3‐phenyl‐2‐aminocyclobutane‐1‐carboxylic acid the resolution with chiral oxazolidin‐2‐one is demonstrated to allow access to both enantiomers. Alternatively, a chiral auxiliary approach led as well to the enantiomerically pure target compound. Finally, the synthesis of either enantiomer of 3‐(aminomethyl)‐5‐phenylpentanoic acid, the racemate being described as an anticonvulsant, is described.