Chemo-enzymatic synthesis of the azasugars 1,4-dideoxyallonojirimycin and 1,4-dideoxymannojirimycin

Synthesis, resolution, and determination of absolute configuration of protected α-ethynylphenylalanine enantiomers

“…We use Bestmann-Ohira method to obtain alkyne 6 in 74 % yield after purification by column chromatography because of the mild conditions applied (Ohira 1989;Muller et al 1996, Meffre et al 2002) (Scheme 2). Several attempts to carry out the selective deprotection of the isopropylidene group of 6 failed: Sc(OTf) 3 (10 mol %) (Avenoza et al 1999b), CuCl 2 .2H 2 O (Venkataiah et al 2011), BiBr 3 (Cong et al 2005), Pyridinium paratoluenesulfonate (Clerc et al 2010). The successfulness of this transformation is known to be highly substrate dependant.…”

From racemic precursors to fully stereocontrolled products: one-pot synthesis of chiral α-amino lactones and lactams

“…4 In spite of their promising biological activities, the stereocontrolled synthesis of chiral α-amino lactones or lactams with multiple stereogenic centers has remained a challenging issue. Indeed, among the documented examples, a stepwise process is generally involved in the formation of all chiral centers on the ring system of lactones or lactams, and relies mainly on the application of enzymatic resolution, 5 chiral auxiliaries, 6 or chiral starting materials. 7 In addition, most cases still suffered from several related drawbacks, including low efficiency, 8 costly transition metal catalysis, 9 or scope restrictions.…”

Synthesis of α-Benzyloxyamino-γ-butyrolactones via a Polar Radical Crossover Cycloaddition Reaction

“…They have also been used in the synthesis of antibiotics, antifungal peptides, and serine protease inhibitors. 6 This class of lactones has also demonstrated antitumor and anticancer activity toward human colorectal and breast cancer cell lines. 7 Given their importance, several strategies have been developed to construct α-amino-γ-butyrolactones.…”

“… , Such communication between microorganisms controls the growth of biofilms and virulence factor production. They have also been used in the synthesis of antibiotics, antifungal peptides, and serine protease inhibitors . This class of lactones has also demonstrated antitumor and anticancer activity toward human colorectal and breast cancer cell lines …”

“…Given their importance, several strategies have been developed to construct α-amino-γ-butyrolactones. The most common method used to generate this class of lactones is through the cyclization of amino acid derivatives, particularly methionine and aspartic acid. ,,− However, this strategy limits the substitution pattern and functionality around the lactone ring. Other intramolecular cyclizations have been utilized, including the acid-mediated ring closure of α-amino-γ,δ-unsaturated carboxylic acid esters and the enzymatic cyclization of α-amino ketoesters .…”