A novel [3 + 2] annulation between para-quinone methides and vinylcyclopropanes for the synthesis of spiro[4.5]deca-6,9-diene-8-ones has been described. The palladium phosphine-thiourea cooperative catalysis system played an important role in high yields diastereoselectivities. reaction exhibited good functional group tolerance scalability.

A formal 1,6-conjugated addition-mediated [2+1] annulation to synthesize spiro[2.5]octa-4,7-dien-6-one with p-quinone methides and sulfur ylides has been described. This domino-type process was highly diastereoselective exhibited good functional group tolerance scalability without the use of metals bases.

A 1,6‐addition arylation reaction of para ‐quinone methides with α‐isocyanoacetamides and electron‐rich aromatic compounds under metal‐free conditions has been developed. BF 3 · Et 2 O plays two roles in the reaction: catalyzing cyclization to give oxazoles, activating achieve process. The shows good functional group tolerance, scalability, regioselectivity. It is a consice protocol for synthesis diverse unsymmetrical triarylmethanes. Further transformation resulting triarylmethanes provides...

Abstract Plant-derived alkaloids are an important class of pharmaceuticals. However, they still rely on phytoextraction to meet their diverse market demands. Since multistep biocatalytic cascades have begun revolutionize the manufacture natural or unnatural products, address synthetic challenges alkaloids, herein we establish artificially concise four-enzyme cascade with avoiding plant-derived P450 modification for synthesizing phenethylisoquinoline (PEIAs) after enzyme discovery and...

2,3-Dihydrobenzofurans were achieved <italic>via</italic> a 1,6-conjugated addition-mediated [4 + 1] annulation of <italic>ortho</italic>-hydroxyphenyl-substituted <italic>para</italic>-quinone methides in high yields with diastereoselectivity.

Abstract A palladium‐catalyzed asymmetric reductive Heck reaction of unactivated aliphatic alkenes, with eliminable β‐hydrogen atoms, has been realized for the first time. series optically active bicyclo[3.2.1]octanes bearing chiral quaternary and tertiary carbon stereocenters were obtained in good yields excellent enantioselectivities, exhibiting functional‐group tolerance scalability. Moreover, deuterated also high efficiency.

Abstract Transition-metal-catalyzed tandem Heck/carbonylation reaction has emerged as a powerful tool for the synthesis of structurally diverse carbonyl molecules, well natural products and pharmaceuticals. However, asymmetric version was rarely reported, remains challenging topic. Herein, we describe palladium-catalyzed desymmetrization cyclopentenes. Alcohols, phenols amines are employed versatile coupling reagents construction multifunctional chiral bicyclo[3.2.1]octanes with one...

Owing to zero-calorie and advanced organoleptic properties similar sucrose, the plant-derived rebaudioside M (Reb M) has been considered as a next generation sweetener. However, low content of Reb in Stevia rebaudiana Bertoni enzymatic activity UGT76G1, which is an uridine diphosphate glucose (UDPG)-dependent glycosyltransferase with ability glycosylate D D) produce through formation β-1,3 glycosidic bond, restrict its commercial usage. To improve catalytic variant UGT76G1-T284S/M88L/L200A...

New-to-nature biocatalysis in organic synthesis has recently emerged as a green and powerful strategy for the preparation of valuable chiral products, among which oxygen-containing benzo-fused heterocycles are important structural motifs pharmaceutical industry. However, asymmetric these compounds through radical-mediated methods is challenging. Herein, novel photoenzymatic developed to realize efficient enantioselective structure-guided engineering flavin-dependent 'ene'-reductase GluER. It...

An atypical nonheme iron-dependent dioxygenase BTG13 with a rare iron coordination of four histidine residues and carboxylated-lysine (Kcx) was recently reported to catalyze the C4a–C10 bond cleavage anthraquinone. However, reaction mechanism remains elusive. Herein, detailed is studied using molecular dynamics simulations density functional theory calculations. The comprehensive mechanistic study shows that most favorable pathway for C–C anthraquinone involves two unusual steps: (1)...

Abstract A palladium‐catalyzed oxa‐[4+2] annulation of para ‐quinone methides with allyl carbonates bearing a nucleophilic alcohol side chain has been developed. This method provided an efficient strategy to the construction 2‐oxaspiro‐cyclohexadienones via 1,6‐conjugated addition‐mediated allylation in moderate good yields. Preliminary results on asymmetric derivatives promised potential synthesis enantioenriched frameworks. magnified image

An unprecedented silver-catalyzed cascade 1,6-addition/5-exo-dig cyclization reaction between para-quinone methides and propargyl malonates under mild conditions has been described. This provides an efficient method to construct versatile spiro[4.5]cyclohexadienones in moderate excellent yields with high atom economy scalability.

Abstract The construction of structural complexity and diversity natural products is crucial for drug discovery development. To overcome high dark toxicity poor photostability photosensitizer perylenequinones (PQs) photodynamic therapy, herein, we aim to introduce the biosynthesize desired unnatural PQs in fungus Cercospora through synthetic biology‐based strategy. Thus, first elucidate intricate biosynthetic pathways class B reveal how branching enzymes create their from a common ancestor....

The successful biomimetic or chemoenzymatic synthesis of target natural products (NPs) and their derivatives relies on enzyme discovery. Herein, we discover a fungal P450 BTG5 that can catalyze the formation bicyclo[3.2.2]nonane structure through an unusual two-step mechanism dimerization cyclization in biosynthesis beticolin 1, whose skeleton connects anthraquinone moiety xanthone moiety. Further investigation reveals BTG5-T318 not only determines substrate selectivity but also alters...

Steviol glycosides (SGs) are highly valued for their sweetness, safety, and zero calories, but bitter taste low solubility limit application. Modifying glycosyl units is a promising strategy to improve sensory qualities. In this study, we identified the enzyme UGT94E13 through phylogenetic analysis screening, which catalyzes glycosylation of rebaudioside M2 (Reb M2) at C-13 position, producing novel β-1,6-O-glycosylated product M9 M9). Subsequently, catalytic activity toward Reb was enhanced...

A tandem 1,6-addition/cyclization/vinylcyclopropane rearrangement for the synthesis of spiro[4.5]cyclohexadienones at low temperature under metal-free conditions is reported.

Abstract An unprecedented [4+2] cycloaddition of in situ generated azoalkenes with arylacetic acids has been developed under the catalysis isothiourea. The reaction provided an efficient approach to synthesis 4,5‐dihydropyridazin‐3(2 H )‐one derivatives moderate good yields (up 95%). magnified image

Methylenedioxy bridges (MDBs) are architecturally important motifs in natural products and bioactive molecules. Cercosporin, a typical perylenequinone pigment, contains an unusual seven-membered MDB, which has versatile biological photocatalytic activities. Although cercosporin been isolated, characterized, studied for several decades, its biosynthetic pathway, especially the formation of remained unclear. Here, we show that MDB is catalyzed by Fe(II)/α-ketoglutaric acid (α-KG)-dependent...

This study used light-mediated comparative transcriptomics to identify the biosynthetic gene cluster of beticolin 1 in Cercospora. It contains an anthraquinone moiety and unusual halogenated xanthone connected by a bicyclo[3.2.2]nonane. During elucidation pathway 1, novel non-heme iron oxygenase BTG13 responsible for ring cleavage was discovered. More importantly, discovery is well supported experimental evidence: (i) crystal structure inductively coupled plasma mass spectrometry revealed...