Sophie K. Bertilsson

The aza-Diels–Alder reaction protocol—a useful approach to chiral, sterically constrained α-amino acid derivatives

Abstract Different types of polycyclic α-amino acid derivatives are prepared from chiral imines by using well-established aza-Diels–Alder reaction conditions. Simply by varying the diene moiety, different products such as spirocyclic compounds 8 and 9, anthracene 10, and tetrahydroquinolines 15–21 are formed.

Asymmetric base-promoted epoxide rearrangement: achiral lithium amides revisited

The use of achiral bases other than lithium diisopropylamide (LDA) was investigated for the asymmetric (1S,3R,4R)-3-(pyrrolidinyl)methyl-2-azabicyclo[2.2.1]heptane catalyzed rearrangement of cyclohexene oxide to (1R)-cyclohex-2-en-1-ol. No significant improvement of the reaction protocol was achieved although some interesting trends were observed. The enantioselectivity in the cyclohexene oxide rearrangement was however markedly improved by slow addition of the achiral base.

A rigid dirhodium(II) carboxylate as an efficient catalyst for the asymmetric cyclopropanation of olefins

The dirhodium(II) complex 7 of (1S,3R,4R)-2-(p-tert-butylphenylsulphonyl)-2-aza-bicyclo[2.2.1]heptane-3-carboxylic acid (3) (or its enantiomer) was synthesised in four steps from cyclopentadiene, (R)- or (S)-phenylethylamine and methyl glyoxylate. Complex 7 was evaluated as a catalyst in the asymmetric cyclopropanation of alkenes with vinyl- and phenyl-diazoesters, resulting in enantioselectivity of up to 92%.