350482-54-1Relevant academic research and scientific papers
Asymmetric Synthesis of α,β-Unsaturated δ-Lactones through Copper(I)-Catalyzed Direct Vinylogous Aldol Reaction
Zhang, Hai-Jun,Yin, Liang
supporting information, p. 12270 - 12279 (2018/09/25)
A simple methodology for the asymmetric synthesis of chiral α,β-unsaturated δ-lactones was achieved by copper(I)-catalyzed direct vinylogous aldol reaction (DVAR) of β,γ-unsaturated esters and various aldehydes, including aromatic aldehydes, heteroaromatic aldehydes, α,β-unsaturated aldehydes, and aliphatic aldehydes. For aromatic and heteroaromatic aldehydes, a one-pot reaction consisting of DVAR, isomerization of the unsaturated carbon-carbon double bond from (E)-form to (Z)-form, and subsequent intramolecular transesterification was required to get the lactones in moderate to high yields with high enantioselectivity. For α,β-unsaturated and aliphatic aldehydes, the DVAR proceeded directly to afford the lactones in moderate yields with high enantioselectivity. In the DVAR, various functional groups were well tolerated. Moreover, the methodology was nicely applicable to the aldehyde group distributed in natural products, derivatives of natural product, and derivatives of drug molecules (atomoxetine and naproxen). The mechanism studies revealed that α-addition was reversible and not favored, which accounted for the excellent regioselectivity in the DVAR. The copper(I)-dienolate species generated through deprotonation was proposed to form an equilibrium with an allylcopper(I) species, which reacted with aldehydes to afford the DVAR products through a catalytic asymmetric allylation of aldehydes. Finally, the robustness of the present reaction was demonstrated by a gram-scale reaction, and the utility of the present methodology was showcased by the formal asymmetric synthesis of ezetimibe and fostriecin.
Structure elucidation and enantioselective total synthesis of the HMG-CoA reductase inhibitors FR901512 and FR901516
Inoue, Masahiro,Nakada, Masahisa
scheme or table, p. 3694 - 3707 (2010/03/30)
The enantioselective total synthesis of the potent HMGCoA reductase inhibitors FR901512 (1) and FR901516 (2) is reviewed. FR901512 was prepared in 15 steps from commercially available compound via 2 in 16.3% overall yield (89% average yield). This study validated the applicability and reliability of the catalytic asymmetric Nozaki-Hiyama reactions that were developed by us. These reactions enabled the concise, efficient, and protecting-group-free enantioselective total syntheses of these new statins.
