Desymmetrization of 1-Symmetrical Donor–Acceptor (D–A) Cyclopropanes via Reactions with 1,3-Cyclodiones

Abstract

A new type of 1-unsymmetrical D–A cyclopropanes containing a cyclic enone motif was obtained by the desymmetrization of 1-symmetrical D–A cyclopropanes via first the Lewis acid-catalyzed O-nucleophilic ring-opening reaction with 1,3-cyclodiones followed by an organobase-promoted unexpected multistep intramolecular transformation.

Catalytic asymmetric ring-opening of aminocyclopropanes with oxygen nucleophiles: access to chiral γ-amino acid derivatives

“…nucleophiles, 17 the corresponding chiral γ-oxygen-substituted GABA derivatives 11aa-11ac were produced in 71-82% yields and 93-97% ee (Scheme 4c).…”

“…When the reaction temperature was increased, the reactivity improved obviously, along with slightly decreased enantioselectivity. Applying 1,3-cyclodiones 10a–10c as oxygen nucleophiles, 17 the corresponding chiral γ-oxygen-substituted GABA derivatives 11aa–11ac were produced in 71–82% yields and 93–97% ee (Scheme 4c).…”

Ambident reactivity of 5-aminopyrazoles towards donor–acceptor cyclopropanes

“…Similarly, enols and phenols, the most studied organic ambident nucleophiles, are known to attack DA cyclopropanes by either C- or O-atoms, the C-attack being a predominant process. 4,5 Oppositely, for NH -anilines, the nucleophilic DA cyclopropane opening solely via a nitrogen atom attack has been documented to date 6–10 (Scheme 1a). Such behaviour of arene derivatives is apparently explained by the loss of aromatic stabilisation energy during the C-attack providing a higher energy barrier for the C-attack in comparison with the N-attack in reactions of anilines and the O-attack of phenolates.…”

Synthesis of (Het)aryl 2-(2-hydroxyaryl)cyclopropyl Ketones

“…During last decades donor-acceptor (D-A) cyclopropanes [1][2][3][4][5][6] attracted a significant attention of organic chemists due to the excellent combination of their availability and high reactivity toward diverse classes of reaction partners: nucleophiles [4,[7][8][9][10], electrophiles [11,12], radicals [13,14], dipolarophiles [15][16][17][18][19][20][21][22], dipoles [23][24][25], 1,3-dienes [26][27][28], etc. (Scheme 1a).…”