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Herein, we present a comprehensive total synthesis of cannabidiol integrating both batch and continuous flow conditions. Our approach is planned to streamline the synthesis of olivetolic acid derivatives and utilize an enantiomerically pure monoterpene moiety obtained from naturally occurring (R)‐(+)‐limonene by photocatalysis. Key reactions, including the synthesis of olivetolic ester and a Friedel‐Crafts alkylation, are successfully adapted to continuous flow, resulting in improved yields and selectivities. This study not only offers a scalable and efficient route for cannabidiol synthesis but also contributes to the synthetic approaches to access cannabinoids (diversity synthesis), with potential applications in medicinal and industrial contexts. [ABSTRACT FROM AUTHOR]

Pralidoxime salts are important medical countermeasures towards different organophosphorus compounds, either nerve agents or pesticides, as they act as acetylcholinesterase reactivators, avoiding health issues and even death that can result from intoxication with such chemicals. In this work, we present an expeditious study focuses on the optimization of a two‐step continuous‐flow synthesis of 2‐PAM. Initial attempts to replace the solvent composition in the oxime formation reaction with acetonitrile resulted in lower yields, highlighting the significance of a polar protic solvent. Subsequent optimization under continuous‐flow conditions revealed the successful execution of oxime formation at room temperature with a residence time of 20 minutes, achieving an impressive 96 % conversion, surpassing literature‐reported conditions. The methylation step required a high residence time of 60 minutes at 120 °C for a substantial conversion of 78 %. The two‐step continuous‐flow process demonstrated robustness, yielding 75 %, with space‐time yields of 0.32 g/h and 0.18 g/h. Further concentration adjustments increased space‐time yields to 3.2 g/h and 2.2 g/h. Despite solvent incompatibility, a strategic alteration of the reaction sequence allowed for a successful cascade process, integrating the methylation step in acetonitrile and the oxime formation in water. The continuous‐flow system, incorporating a heat exchanger, exhibited stability, maintaining full conversion and a space‐time yield of 0.3 g/h over extended periods. This systematic optimization not only enhances the efficiency of 2‐PAM synthesis but also provides insights into a scalable and practical continuous‐flow cascade process. [ABSTRACT FROM AUTHOR]

This study investigated the oxidation of 5-hydroxymethylfurfural (HMF) to produce valuable products such as 2,5-furandicarboxaldehyde (DFF), 5-formyl-2-furancarboxylic acid (FFCA) and 2,5-furandicarboxylic acid (FDCA) through (photo) chemical and enzymatic catalysis. Laccases from different sources, including Aspergillus spp., Pseudomonas cepacea, and Trametes versicolor, were evaluated for their catalytic activity in the HMF oxidation. Laccase from Trametes versicolor (LacTV) emerged as the most effective catalyst, achieving complete conversion of HMF under specific pH conditions. The reaction mechanisms were explored, revealing a preference for the primary alcohol oxidation pathway over the aldehyde, leading to the formation of DFF and subsequent conversion to FFCA and FDCA. The impact of substrate concentration on HMF conversion was examined, revealing optimal conversion at lower HMF concentrations (<100 mM) and reduced performance at higher concentrations (>100 mM). The study also examined the influence of blue light (430 nm) on this reaction, revealing the dependence on light exposure for gC3N4 based catalysts and a negative effect for LacTV. Furthermore, the study introduces a modular flow chemical platform that utilizes Continuous Stirred Tank Reactors (CSTR) in a cascade configuration, the optimization of HMF oxidation. The implementation of this innovative approach has led to the effective synthesis of FDCA, demonstrating an impressive 40-fold increase in productivity compared to the traditional batch system. These results present significant potential for advancing green chemistry and sustainable chemical synthesis, introducing novel possibilities for environmentally friendly HMF oxidation processes. [ABSTRACT FROM AUTHOR]

Certified reference materials (CRM) of amphetamine derivatives were produced through a simple, rapid and efficient synthesis in both batch and continuous‐flow conditions, accompanied by the development of a comprehensive certification protocol for this class of substances. Our chemistry enabled the synthesis of MDA, MDMA, PMA and PMMA in two steps from safrole and estragole with overall yields of 38–61 % in 48 hours under batch conditions and 61–65 % in 65 minutes under continuous‐flow conditions, followed by the development of a certification protocol for these materials through identity checking, homogeneity, stability, and characterization studies. Furthermore, as result of this work, a very pure CRM of MDA.HCl with 99.1±1.4 g/100 g of certified characterization value was produced. Considering the importance of supplying amphetamine calibrants for public security efforts in Forensic Chemistry, the potential therapeutical applications, and responding to the rising demand for the synthesis of CRM, this work presents a pioneering approach for the production of amphetamine and related compounds. [ABSTRACT FROM AUTHOR]

A visible-light-driven photocatalytic decarboxylation of palmitic acid and related fatty acids is described in this study. Remarkable decarboxylation rates have been observed with full conversion in less than 20 min. In this study, we have demonstrated that sunlight irradiation, even on cloudy days, can deliver similar results to traditional LED lamps while using much less energy and minimizing environmental impact. The findings indicate that the process of enzymatic decarboxylation could be useful for the production of different biofuels in the future. [ABSTRACT FROM AUTHOR]

l‐Methionine γ‐lyase (MGL) is a PLP‐dependent enzyme which catalyzes the α, γ‐elimination reaction in sulfur containing amino acids, such as L‐methionine and L‐cysteine. Its major applications are on metabolic restriction of methionine to cancer cells, food industry (cheese flavor) and for the synthesis of d and l‐homoalanine. Herein, we present the immobilization and use of this new immobilized biocatalyst under batch and continuous‐flow conditions. The best optimized continuous‐flow condition allowed 89 % conversion in 30 min of residence time with good recyclability of the biocatalyst. [ABSTRACT FROM AUTHOR]

Bonding to different dental restorative materials is challenging. This study aimed to evaluate the effect of a 10-MDP-based dentin adhesive on the shear bond strength (SBS) of self-adhesive resin cement (RC) to implant abutment materials. One hundred and twenty specimens were obtained from zirconia (ZO), cobalt-chromium alloy (CoCr), and commercially pure titanium (Ti), which were treated as follows (n = 10): control group—non-treated (CG), 10-MDP-based dentin adhesive (SB), light-cured SB (SB-LC), and zirconia primer (ZP). Blocks of RC were buildup and, after 24 h, were tested for bond strength. Data of SBS (MPa) were submitted to two-way ANOVA and Tukey test (α = 0.05). There was no difference in SBS among materials for CG and ZP, higher SBS were recorded for Ti SB and Ti SB-LC compared to ZO upon the same surface treatments. For the comparisons among treatments, SB-LC showed the highest SBS for CoCr. For ZO and Ti, higher SBS were recorded with SB and SB-LC. No cohesive failures were observed. It was concluded that the surface treatment with 10-MDP-based materials increased the bond strength of the resin cement to abutment materials, which showed to be material dependent. [ABSTRACT FROM AUTHOR]

The objective of this study was to assess the influence of the extension of collar and fatigue cycling on the fracture load of anterior zirconia crowns. A total of 60 anterior full-crown preparations (central incisor) were machined in glass fiber– filled epoxy resin. Zirconia copings were designed and milled using computeraided design/computer-assisted manufacture (thickness: buccal = 0.62 mm, lingual = 0.65 mm, incisal = 0.72 mm). The cervical collars (occlusogingival height = 0.8 mm, buccolingual width = 1.0 mm) were totally or partially (buccal face) removed for modified copings. They were randomly allocated to six groups according to the type of cervical collar design and the presence (or not) of fatigue cycling (n = 10). The veneering ceramic layer was pressed, and the crowns were cemented with resin cement. The samples were tested until fracture in a universal testing machine and analyzed by stereomicroscopy. Data were statistically analyzed by two-way analysis of variance and Tukey test (5%). Removal of the cervical collar significantly affected the fracture strength of zirconia crowns (P = .000), whereas fatigue cycling did not (P = .428). The mean failure load was lower in the groups with no collar. The most frequent failure modes were cracking of the veneer porcelain in collarless crowns and catastrophic failure in the others. The authors concluded that removal of the vestibular collar of zirconia copings in anterior crowns does not reduce the fracture load of the crowns. However, removal of the entire collar reduces the fracture load and cannot be recommended. [ABSTRACT FROM AUTHOR]

The required connector dimension for zirconia fixed dental prostheses (FDPs) may be a clinical limitation due to limited space in the occlusogingival direction. Using no veneering in the gingival regions of the pontics and connectors may solve this problem. This study evaluated the mechanical durability of zirconia FDPs with and without veneering in the gingival area of the connectors and pontics and subsequent airabrasion of this region with different protocols. Models were made of resin abutments (diameter = 6 or 8 mm, height = 6 mm, 6 degrees convergence) and embedded in polyurethane resin (distance = 11 mm). Zirconia frameworks were milled and randomly distributed by veneering (veneering of the entire framework [VEN] or no veneering at gingival regions of the pontic and connector [NVEN]) and by air-abrasion (Al2O3/SiO2, 30 μm; or 45 μm Al2O3. FDPs were adhesively cemented and subjected to mechanical cycling (1,200,000 cycles, 200 N, 4 Hz, with water cooling). Specimens were tested until fracture (1 mm/min), and failure modes were classified. Data (N) were subjected to one-way analysis of variance in two sets, Tukey test (α = .05) and Weibull analysis. While veneering did not significantly affect the results (VEN: 1,958 ± 299 N; NVEN: 1,788 ± 152 N; P = .094), air abrasion did (P = .006), with the worst results for the groups conditioned with 45 μm Al2O3 (SiO2: 1,748 ± 273 N; Al2O3: 1,512 ± 174 N). The NVEN group demonstrated the highest Weibull modulus (12.8) compared with the other groups (5.3–7.2). Fractures commonly initiated from the gingival side of the connector. Veneering of the gingival region of the connectors and pontics in zirconia FDPs did not diminish the fracture strength, but air-abrasion of this area with 45 μm Al2O3 decreased the results. [ABSTRACT FROM AUTHOR]

The current state of evidence and recommendations for cannabidiol (CBD) and its health effects change the legal landscape and aim to destigmatize its phytotherapeutic research. Recently, some countries have included CBD as an antiepileptic product for compassionate use in children with refractory epilepsy. The growing demand for CBD has led to the need for high‐purity cannabinoids on the emerging market. The discovery and development of approaches toward CBD synthesis have arisen from the successful extraction of Cannabis plants for cannabinoid fermentation in brewer's yeast. To understand different contributions to the design and enhancement of the synthesis of CBD and its key intermediates, a detailed analysis of the history behind cannabinoid compounds and their optimization is provided herein. [ABSTRACT FROM AUTHOR]

The development of efficient catalytic systems is a fundamental aspect for the straightforward production of chemicals. During the last years, covalent organic frameworks (COFs) emerged as an exciting class of organic nanoporous materials. Due to their pre‐designable structure, they can be prepared with distinct physicochemical characteristics, specific pore sizes, and tunable functional groups. Moreover, associated with their stability in different media, these materials are considered promising supports for enzyme immobilization. Herein, it is highlighted the recent literature of enzyme immobilization in COFs, the main immobilization strategies, and the catalytic applications of these composites. [ABSTRACT FROM AUTHOR]

This study assessed alterations on bovine enamel after excessive bleaching. Coronal portions of bovine teeth (n = 30) were sectioned and divided into three groups (n = 10 per group). The coronal parts were further cut incisocervically into two halves. While one half received no bleaching (control), the other half was subjected to either one (group 1), three (group 2), or five bleaching sessions (group 3) with 35% hydrogen peroxide. The enamel surfaces were then analyzed using scanning electron microscopy and energy dispersive x-ray spectroscopy (EDS). Excessive bleaching affected the surface morphology and chemistry of the bovine enamel. EDS analysis showed the highest decrease in calcium ion percentages in groups 2 and 3 when compared to their nonbleached halves. Oxygen and phosphorus percentages were comparable on both the control and bleached enamel, regardless of the number of bleaching sessions. Consecutive bleaching sessions with 35% hydrogen peroxide may lead to morphologic and specific elemental changes when performed in a short period of time. Calcium ion percentages may decrease when this bleaching agent is used for more than one session. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the influence of the brush type as a carrier of priming adhesive solutions and the use of paper points as a remover of the excess of these solutions on the push-out bond strength of resin cement to bovine root dentin. The null hypotheses were that brush type and the use of paper points do not affect the bond strength. Materials and Methods: The canals of 80 single-root bovine roots (16 mm in length) were prepared at 12 mm using the preparation drill (FRC Postec Plus, Ivoclar). Half of each root was embedded in acrylic resin and the specimens were divided into 8 groups, considering the factors "brush type" (4 levels) and "paper point" (2 levels) (n = 10): Gr 1: small microbrush (Cavi-Tip, SDI); Gr 2: Microbrush (Dentsply); Gr 3: Endobrush (Bisco); Gr 4: conventional brush (Bisco); Gr 5: Cavi-Tip (SDI) + paper points; Gr 6: Microbrush (Dentsply) + paper points; Gr 7: Endobrush (Bisco) + paper points; Gr 8: conventional brush (Bisco) + paper points. The root dentin was treated with a multistep total-etch adhesive system (All Bond 2). The adhesive system was applied using each microbrush, with and without using paper points. One fiber post was molded with addition silicon and 80 posts were made of resin cement (Duolink). The resin posts were luted (Duolink resin cement), and the specimens were stored for 24 h in water at 37°C. Each specimen was cut into 4 disk-shaped samples (1.8 mm in thickness), which were submitted to the push-out test. Results: The brush type (p > 0.0001) (small microbrush > microbrush = endobrush = conventional brush) and the use of paper points (p = 0.0001) (with > without) influenced the bond strength significantly (two-way ANOVA). The null hypotheses were rejected. Conclusion: The smallest brush (Cavi-Tip) and the use of paper points significantly improved the resin bond to bovine root dentin. [ABSTRACT FROM AUTHOR]

Sustainability in chemistry heavily relies on heterogeneous catalysis. Enzymes, the main catalyst for biochemical reactions in nature, are an elegant choice to catalyze reactions due to their high activity and selectivity, although they usually suffer from lack of robustness. To overcome this drawback, enzyme‐decorated nanoporous heterogeneous catalysts were developed. Three different approaches for Candida antarctica lipase B (CAL‐B) immobilization on a covalent organic framework (PPF‐2) were employed: physical adsorption on the surface, covalent attachment of the enzyme in functional groups on the surface and covalent attachment into a linker added post‐synthesis. The influence of the immobilization strategy on the enzyme uptake, specific activity, thermal stability, and the possibility of its use through multiple cycles was explored. High specific activities were observed for PPF‐2‐supported CAL‐B in the esterification of oleic acid with ethanol, ranging from 58 to 283 U mg−1, which was 2.6 to 12.7 times greater than the observed for the commercial Novozyme 435. [ABSTRACT FROM AUTHOR]

The combination of chiral supported‐organocatalysts and flow chemistry promotes the sustainable production of enantioenriched compounds providing a very powerful tool for chemical and pharmaceutical industries. However, the rapid deactivation of these catalysts in heterogeneous asymmetric reactions has been limiting the expansion of the area. In this work we report for the first time the advantages of synthesizing, immobilizing, and using a silica‐supported organocatalyst under a complete continuous‐flow approach, showing the impact of this method on the morphology, structure and lifetime of the organocatalyst. The first generation MacMillan's organocatalyst was prepared from L‐phenylalanine and immobilized in silica through a carbamate linkage under batch and continuous‐flow conditions. We also evaluated the performance of both batch and continuous‐flow organocatalysts in the Diels‐Alder reaction for proof of concept. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the morphology of filler particles, chemical composition, microhardness (MH), water sorption (WSp), and solubility (WSl) of a regular viscosity bulk fill and traditional composite resins. Methods: Eighty samples (Ø:5 mm; height: 4 mm) were prepared according to the factors "composite" (Aura/SDI, FiltekZ250 XT/3M, Aura Bulk Fill/SDI, and Filtek Bulk Fill/3M) and "filling technique" (incremental and bulk) (n = 10). Vickers MH was measured on the top and bottom surfaces of each samples, and then WSp and WSl were obtained by means of mass gain and loss. Morphology of filler particles and chemical characteristics of composites were evaluated by scanning electron microscopy (SEM) and energy dispersity spectroscopy (EDS) in additional samples (n = 1/group). Data were analyzed using two‐ and three‐way ANOVA and Tukey's tests (p < .05). Results: No significant difference was found for WSp among the groups. Comparing composites in the incremental technique, Aura bulk fill composite showed lower WSI than the other materials and in the bulk fill technique, Filtek Bulk Fill showed the lowest value. Filtek Bulk Fill showed higher MH than the other composites on the bottom surface when samples were produced by bulk filling. Conclusion: The composites presented good physical properties, but the bulk fill ones showed better results for the bottom microhardness and solubility, although chemical elements and morphology were similar in general. [ABSTRACT FROM AUTHOR]

Unnatural amino acids attract growing attention for pharmaceutical applications as they are useful building blocks for the synthesis of a number of chiral drugs. Here, we describe a two‐step enzymatic method for the asymmetric synthesis of homoalanine from L‐methionine, a cheap and readily available natural amino acid. First, the enzyme L‐methionine γ‐lyase (METase), from Fusobacterium nucleatum, catalyzed the γ‐elimination of L‐methionine to 2‐oxobutyrate. Second, an amino acid aminotransferase catalyzed the asymmetric conversion of 2‐oxobutyrate to either L‐ or D‐homoalanine. The L‐branched chain amino acid aminotransferase from Escherichia coli (eBCAT), using L‐glutamate as amino donor, produced L‐homoalanine (32.5 % conv. 28 % y, 99 % ee) and the D‐amino acid aminotransferase from Bacillus sp. (DATA) used D‐alanine as amino donor to produce D‐homoalanine (87.5 % conv. 69 % y, 90 % ee). Thus, this concept allows for the first time the synthesis of both enantiomers of this important unnatural amino acid. For the very first time! Unnatural amino acids have important applications in pharmaceutical chemistry. A biocatalytic cascade is described providing access to both, l‐ and d‐homoalanine, using a combination of a l‐methionine γ‐lyase (METase) and two amino acid transaminases with complementary enantiopreference. [ABSTRACT FROM AUTHOR]

The combination of enzymatic and chemical reaction steps is one important area of research in organic synthesis, preferentially as cascade reactions in one‐pot to improve total conversion and achieve high operational stability. Here, the combination of the Suzuki–Miyaura reaction is described to synthesize biaryl compounds followed by a transamination reaction. Careful optimization of the reaction conditions required for the chemo‐ and biocatalysis reaction enabled an efficient two‐step‐one‐pot reaction yielding the final chiral amines with excellent optical purity (>99 % ee) in up to 84 % total conversion. Key to the success was the protein engineering of the amine transaminases from Asperguillus fumigatus (4CHI‐TA) where single alanine mutations increased the conversion up to 2.3‐fold. Finally, the transfer to a continuous flow system after immobilization of the best 4CHI‐TA variant is demonstrated. The combination of amine transaminase (ATA) activity and the Suzuki–Miyaura cross‐coupling reaction in a two‐step‐one‐pot fashion is presented. The biaryl amines were obtained with high conversion and excellent enantiomeric excess (99 % ee) using isopropylamine as the amine donor after engineering of the transaminase from Asperguillus fumigatus. [ABSTRACT FROM AUTHOR]

Abstract: Amine transaminases (ATA) have now become frequently used biocatalysts in chemo‐enzymatic syntheses including industrial applications. They catalyze the transfer of an amine group from a donor to an acceptor leading to an amine product with high enantiopurity. Hence, they represent an environmentally benign alternative for waste intensive chemical amine synthesis. Isopropylamine (IPA) is probably one of the most favored amine donors since it is cheap and achiral, but nevertheless there is no consistency in literature concerning reaction conditions when IPA is best to be used. At the same time there is still a poor understanding which structural properties in ATA are responsible for IPA acceptance. Herein, we demonstrate, on the basis of the 3FCR enzyme scaffold, a substantial improvement in catalytic activity towards IPA as the amine donor. The asymmetric synthesis of industrial relevant amines was used as model reaction. A systematic investigation of the pH‐value as well as concentration effects using common benchmark substrates and several ATA indicates the necessity of a substrate‐ and ATA‐dependent reaction engineering. [ABSTRACT FROM AUTHOR]

(R)‐Propylene carbonate is an important intermediate in the synthesis of tenofovir pro‐drugs such as tenofovir alafenamide fumarate (TAF) and tenofovir diisoproyl fumarate (TDF). Independent of the pro‐drug type, tenofovir presents a chiral secondary hydroxy derivative, which can be obtained directly from (R)‐propylene carbonate. Herein, we report our chemo‐enzymatic continuous‐flow strategy towards (R)‐propylene carbonate starting from a very cheap and renewable raw material, glycerol. We were able to synthesize (R)‐propylene carbonate in seven continuous‐flow steps, starting from glycerol, in good‐to‐excellent yields (66–93 %) and excellent selectivity (E > 200). [ABSTRACT FROM AUTHOR]

Abstract: Amine transaminases (ATAs) are versatile and industrially relevant biocatalysts that catalyze the transfer of an amine group from a donor to an acceptor molecule. Asymmetric synthesis from a prochiral ketone is the most preferred route to the desired amine product, as it is obtainable in a theoretical yield of 100 %. In addition to the requirement of active and enantioselective ATAs, the choice of a suitable amine donor is also important to save costs and to avoid additional enzymes to shift the equilibrium and/or to recycle the cofactors. In this work, we identified suitable (R)‐ and (S)‐ATAs from Aspergillus fumigatus and Silicibacter pomeroyi, respectively, to afford a set of halogen‐substituted derivatives of brominated or chlorinated 1‐phenyl‐2‐propanamine, 4‐phenylbutan‐2‐amine, and 1‐(3‐pyridinyl)ethanamine. Optimization of the donor–acceptor ratio enabled application of isopropylamine as an amine donor, which resulted in high conversions and amines with 73–99 % ee. [ABSTRACT FROM AUTHOR]

BACKGROUND In this work, lipase B from Candida antarctica (CaLB) was immobilized on Purolite® ECR8205F, Purolite® ECR8214F and Immobead® IB150 P epoxy resins with no modification to their surfaces. Biocatalysts were evaluated for thermal stability and applied in reactions of hydrolysis, esterification and the synthesis of glyceryl carbonate by transesterification with dimethyl-carbonate both with glycerol and Macauba oil as well as dynamic kinetic resolution of α-methylbenzylamine, all of them compared with commercial Novozyme 435®. RESULTS Protein desorption of the biocatalysts with Triton X-100 showed that lipase was immobilized by covalent single-bond type binding. The immobilization efficiencies were 55.1% for the biocatalyst 8205, 57.1% for 8214, and 14.9 for the 150P, demonstrating the intense effect of surface and material composition on lipase immobilization. The biocatalysts also showed higher initial velocities of esterification and hydrolysis reactions as well as higher thermal stability than Novozyme 435®. On glycerol carbonate synthesis, conversion of 97% and selectivity higher than 99% was demonstrated by enzyme 8214, similar to Novozyme 435®. On kinetic dynamic resolution, conversions higher than 94% and and enantiomeric excesses greater than 90% were also depicted. CONCLUSION Compared with commercial preparation Novozyme 435®, the novel biocatalysts obtained by immobilization on new epoxy resins demonstrated protein loads about 10-fold lower and higher specific activity. In all reactions performed, competitive performances were found, demonstrating high potential for industrial applications. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Herein we report a convenient, fast, and high-yielding method for the generation of the racemic amide anaesthetics mepivacaine, ropivacaine, and bupivacaine. Coupling of α-picolinic acid and 2,6-xylidine under sealed-vessel microwave conditions generates the intermediate amide after a reaction time of only 5 min at 150 °C. Subsequent reaction in a continuous-flow high-pressure hydrogenator (H-Cube ProTM) in the presence of the respective aldehyde directly converts the intermediate to the final amide anaesthetics in a continuous, integrated, multi-step ring-hydrogenation/reductive amination protocol. Merits and limitations of the protocol are discussed. [ABSTRACT FROM AUTHOR]

For the planning of an organic synthesis route, the disconnection approach guided by retrosynthetic analysis of possible intermediates and the chemical reactions involved, back to ready available starting materials, is well established. In contrast, such concepts just get developed for biocatalytic routes. In this Review we highlight functional group interconversions catalyzed by enzymes. The article is organized rather by chemical bonds formed-exemplified for C−N, C−O- and C−C-bonds-and not by enzyme classes, covering a broad range of reactions to incorporate the desired functionality in the target molecule. Furthermore, the successful use of biocatalysts, also in combination with chemical steps, is exemplified for the synthesis of various drugs and advanced pharmaceutical intermediates such as Crispine A, Sitagliptin and Atorvastatin. This Review also provides some basic guidelines to choose the most appropriate enzyme for a targeted reaction keeping in mind aspects like commercial availability, cofactor-requirement, solvent tolerance, use of isolated enzymes or whole cell recombinant microorganisms aiming to assist organic chemists in the use of enzymes for synthetic applications. [ABSTRACT FROM AUTHOR]