93578-16-6Relevant articles and documents
Total Synthesis of (-)-Peniphenone A
Pantin, Mathilde,Brimble, Margaret A.,Furkert, Daniel P.
, p. 7049 - 7059 (2018)
The asymmetric total synthesis of the polyketide benzannulated spiroketal natural product, (-)-peniphenone A, is reported. The key reaction in the synthesis involved sp3-sp2 Negishi cross-coupling between a chiral organozinc species and an aryl bromide to construct the challenging α-chiral β-aryl carbonyl motif present in the natural product. Access to the spiroketal possessing the correct stereochemistry was facilitated by an unusual thermodynamic resolution at C10. The synthesis was achieved in 14 steps (longest linear sequence) from commercially available 2,4-dihydroxybenzaldehyde in 6% overall yield. Investigations into a parallel approach required extension of Krische's enantioselective hydrogen-mediated C-C coupling to α-substituted alcohols and oxetane ring-opening with an aryllithium for assembly of the polyketide domain. These studies provide a useful foundation for further work toward the natural product family, members of which demonstrate significant activity against M. tuberculosis and offer continuing inspiration for the development of efficient new chemical methods.
Thioesters as Acyl Donors in Biocatalytic Friedel-Crafts-type Acylation Catalyzed by Acyltransferase from Pseudomonas Protegens
??d?o-Dobrowolska, Anna,Schmidt, Nina G.,Kroutil, Wolfgang
, p. 1064 - 1068 (2019/01/14)
Functionalization of aromatic compounds by acylation has considerable significance in synthetic organic chemistry. As an alternative to chemical Friedel-Crafts acylation, the C-acyltransferase from Pseudomonas protegens has been found to catalyze C?C bond formation with non-natural resorcinol substrates. Extending the scope of acyl donors, it is now shown that the enzyme is also able to catalyze C?S bond cleavage prior to C?C bond formation, thus aliphatic and aromatic thioesters can be used as acyl donors. It is worth to mention that this reaction can be performed in aqueous buffer. Identifying ethyl thioacetate as the most suitable acetyl donor, the products were obtained with up to >99 % conversion and up to 88 % isolated yield without using additional base additives; this represents a significant advancement to prior protocols.
Biocatalytic Friedel–Crafts Acylation and Fries Reaction
Schmidt, Nina G.,Pavkov-Keller, Tea,Richter, Nina,Wiltschi, Birgit,Gruber, Karl,Kroutil, Wolfgang
supporting information, p. 7615 - 7619 (2017/06/13)
The Friedel–Crafts acylation is commonly used for the synthesis of aryl ketones, and a biocatalytic version, which may benefit from the chemo- and regioselectivity of enzymes, has not yet been introduced. Described here is a bacterial acyltransferase which can catalyze Friedel–Crafts C-acylation of phenolic substrates in buffer without the need of CoA-activated reagents. Conversions reach up to >99 %, and various C- or O-acyl donors, such as DAPG or isopropenyl acetate, are accepted by this enzyme. Furthermore the enzyme enables a Fries rearrangement-like reaction of resorcinol derivatives. These findings open an avenue for the development of alternative and selective C?C bond formation methods.
