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A four-step enantiospecific total synthesis of bicyclic homotropinone alkaloid euphococcinine and a racemic synthesis of adaline were reported. Key reactions in the synthesis are the diastereoselective addition of a Wittig phosphorene to the ketimines derived from Davis-Ellman sulfinamides, ring-closing metathesis, and intramolecular Michael reactions.

"Chiral pool" compounds possessing well defined stereocenters and suitable functionality serve as excellent building blocks for the synthesis of natural products and therapeutically important compounds. Tartaric acid is a C2 -symmetric molecule available in both enantiomeric forms. It was extensively utilized in the synthesis of privileged chiral ligands/catalysts such as TADDOLs, and as a start point in the synthesis of plethora of compounds. The advent of several new C-C bond forming reactions offers opportunity for the development of novel synthetic strategies based on chiral pool compounds. We found that the desymmetrization of the bis-dimethyl amide/Weinreb amide derived from tartaric acid can be accomplished by controlled addition of Grignard /organolithium reagents leading to the mono keto amides, the reduction of which affords the γ-hydroxy amides. This account describes our research efforts of more than a decade on the synthesis and application of diverse γ-hydroxy amides derived from tartaric acid in the total synthesis of structurally simple to complex bio-active natural products.

The addition of lithium anion of (acetylmethylene)triphenylphosphorane to nonracemic sulfinimines was investigated. It was found that the addition proceeded with good diastereoselectivity and further reaction of the formed sulfinimidophosphorane with several aldehydes afforded the β-sulfinamido substituted enones in good yields. The resultant enones were elaborated to the synthesis of alkaloid (+)-241D, to the formal total synthesis of (+)-preussin, and to the synthesis of aminocyclopentenol.

The addition of silyl enol ethers obtained from ynones to sulfinimines furnished the corresponding β-sulfinamido ynones in a very good yield and diastereoselectivity. The formed ynones serve as precursors amenable for the synthesis of bioactive compounds. This has been illustrated in the synthesis of l-xylo and l-arabino phytosphingosines.

A regio- and diastereoselective conjugate addition of the lithium anion of N-allyl imine (prepared from allylamine and benzophenone) to α,β-unsaturated esters in good yields is reported. The reaction was general and provided the γ-amino esters resulting from the regioselective C-C bond formation between the α-carbon to the nitrogen in the imine and the β-carbon of the unsaturated ester. Synthetic utility of the formed products was illustrated in the nonracemic total synthesis of the bioactive alkaloid (-)-epibatidine.

The Linear Ubiquitin Assembly Complex (LUBAC), composed of HOIP, HOIL-1L and SHARPIN, promotes Tumor Necrosis Factor (TNF)-dependent NF-κB signaling in diverse cell types. HOIL-1L contains an Npl4 Zinc Finger (NZF) domain that specifically recognizes linear ubiquitin chains, but its physiological role in vivo has remained unclear. Here, we demonstrate that the HOIL-1L NZF domain has important regulatory functions in inflammation and immune responses in mice. We generated knockin mice (Hoil-1lT20;A;R208A/T201A;R208A) expressing a HOIL-1L NZF mutant, and observed attenuated responses to TNF- and LPS-induced shock, including prolonged survival, stabilized body temperature, reduced cytokine production and liver damage markers. Cells derived from the HOIL-1L knockin mice show reduced TNF-dependent NF-κB activation and incomplete recruitment of HOIL-1L into TNF Receptor (TNFR) Complex I. We further show that the HOIL-1L-NZF domain cooperates with SHARPIN to prevent TNFR-dependent skin inflammation. Collectively, our data suggest that linear ubiquitin-chain binding by HOIL-1L regulates immune responses and inflammation in vivo.

Summary The Linear Ubiquitin Chain Assembly Complex (LUBAC), composed of HOIP, HOIL-1L, and SHARPIN, promotes tumor necrosis factor (TNF)-dependent NF-κB signaling in diverse cell types. HOIL-1L contains an Npl4 Zinc Finger (NZF) domain that specifically recognizes linear ubiquitin chains, but its physiological role in vivo has remained unclear. Here, we demonstrate that the HOIL-1L NZF domain has important regulatory functions in inflammation and immune responses in mice. We generated knockin mice (Hoil-1lT201A;R208A/T201A;R208A) expressing a HOIL-1L NZF mutant and observed attenuated responses to TNF- and LPS-induced shock, including prolonged survival, stabilized body temperature, reduced cytokine production, and liver damage markers. Cells derived from Hoil-1lT201A;R208A/T201A;R208A mice show reduced TNF-dependent NF-κB activation and incomplete recruitment of HOIL-1L into TNF Receptor (TNFR) Complex I. We further show that HOIL-1L NZF cooperates with SHARPIN to prevent TNFR-dependent skin inflammation. Collectively, our data suggest that linear ubiquitin-chain binding by HOIL-1L regulates immune responses and inflammation in vivo., Graphical abstract, Highlights • An RBR-type E3 ligase HOIL-1L decodes linear ubiquitin chains via the NZF domain • HOIL-1L NZF is essential for proper responses to LPS and TNF-induced shock in mice • Intact HOIL-1L NZF is required for activating the TNF-induced NF-kB pathway • HOIL-1L NZF cooperates with SHARPIN to control inflammation in mice, Biological sciences; Molecular biology; Immune response

An efficient enantiospecific total synthesis of ent-conduramine F-1 (aminocyclohexenetriol) was accomplished starting from the bis-Weinreb amide of tartaric acid. Key reactions in the synthesis include the desymmetrization of tartaric acid amide with vinylmagnesium bromide and installation of the required amine using Ellman sulfinimine. Ring closing metathesis was used to synthesize the required alkene in the cyclohexene.

Addition of the lithium anion generated from diphenylmethanol methyl and methoxymethyl ether to nonracemic sulfinimines afforded the corresponding addition products in excellent diastereoselctivity and yields. Deprotection of the MOM as well as sulfinyl groups rendered the enantiopure (diphenylhydroxymethyl)amines in excellent yields. The procedure was applied for a two-step synthesis of diphenylprolinol, a privileged ligand in asymmetric catalysis.

Total synthesis of THP tethered pyrone containing natural product cryptopyranmoscatone B2 was accomplished from commercially available 2-deoxyribose. The key THP unit was assembled by FeCl3 catalyzed cyclization of an allyl alcohol. Brown allylation and RCM reactions were employed to construct the lactone unit. The synthesis represents the first total synthesis of the putative structure of the natural product.

A concise total synthesis of the macrolactone natural product Sch 725674 is accomplished starting from commercially available 2-deoxy-o-ribose. Pivotal reactions employed in the synthesis include the addition of 4-pentenylmagnesium bromide to the lactol derived from 2-deoxy-o-ribose, olefin cross metathesis and Yamaguchi macrolactonization. (C) 2018 Elsevier Ltd. All rights reserved.

Synthesis of the 14-membered macrolide core of migrastatin is accomplished by the use of furyl carbinol in 13 linear steps from furfural with ∼11% overall yield. Key strategies in the synthesis include the oxidative ring opening of furan and its use as a four-carbon synthon, SN2 displacement of a functionalized allyl bromide, and ring closing metathesis to obtain the macrolactone.

HOIP, the catalytic component of the Linear Ubiquitin chain Assembly Complex (LUBAC), is a critical regulator of inflammation. However, how HOIP itself is regulated to control inflammatory responses is unclear. Here, we discover that site-specific ubiquitination of K784 within HOIP promotes Tumour Necrosis Factor (TNF)-induced inflammatory signalling by controlling TNF Receptor complex I (TNFR1) formation. A HOIP K784R mutant is catalytically active but shows reduced induction of an NF-κB reporter relative to wild type HOIP. HOIP K784 is evolutionarily conserved, equivalent to HOIP K778 in mice. We generated HoipK778R/K778R knockin mice, which show no overt developmental phenotypes; however, in response to TNF, HoipK778R/K778R mouse embryonic fibroblasts display suppressed NF-κB activation and increased sensitivity to apoptosis. On the other hand, HOIP K778R enhances the TNF-induced formation of TNFR complex II, and an interaction between TNFR complex II and LUBAC. Loss of the LUBAC component SHARPIN leads to embryonic lethality in HoipK778R/K778R mice, which is rescued by knockout of TNFR1. We propose that site-specific ubiquitination of HOIP regulates a LUBAC-dependent switch between survival and apoptosis in TNF-signalling.

First total synthesis of the polyhydroxy 5,6-dihydro-2H-pyrone containing natural products monticolide A and B is reported from tartaric acid. Key reaction is the iridium catalysed redox reaction of the Achmatowicz reaction product to the 5,6-dihydro-2H-pyrone moiety and the use of tartaric acid as a four hydroxy four carbon synthon.

Synthesis of chiral tetrols and 1,2,4-triols with varied substitutions was accomplished from tartaric acid. Pivotal reaction in the synthesis was the use of Ley's dithianylation of an alkynyl ketone derived from tartaric acid. Application of the strategy was demonstrated in the total synthesis of decanolactone achaetolide.

Addition of silyl enol ethers obtained from substituted methyl enones to chiral sulfinimines afforded the β-amino-substituted enones with excellent selectivity. Utility of the obtained N-sulfinyl β-amino ketones possessing α,β-unsaturation is exemplified in the total synthesis of the quinolizidine alkaloid natural products (-)-lasubine I, (+)-lasubine II, and substituted piperidine alkaloid (+)-241-D.

Synthesis of novel C2-symmetric 1,2- 1,3- and 1,4- bis-sulfinamides and their use as effective ligands in rhodium (I) catalyzed asymmetric conjugate addition of arylboronic acids to cyclohexenone and cyclopentenones is described. C2-symmetry as well as chirality at the sulfur center in the ligand is crucial for the high enantioselectivity in the 1,4-addition reaction. It was also observed that the conjugate addition proceeded with good selectivity with Wilkinson's catalyst as the rhodium source.

Enantioselective total synthesis of δ-lactone containing natural product (−)-cryptofolione was accomplished from commercially available benzylidene acetone. Key features of the synthesis include lipase mediated resolution of a β-hydroxy ketone intermediate, DBU mediated isomerization of γ,δ-unsaturated aldehyde to α,β-unsaturated aldehyde, Brown allylation and RCM reactions.

The synthesis of 2,3,4,6-tetrasubstituted tetrahydropyran unit of ratjadone A was achieved. Pivotal reaction sequence in the synthesis include non-Evans syn aldol reaction of a chiral aldehyde obtained from l -malic acid and Uenishi’s palladium catalyzed stereoselective intramolecular SN2′ reaction to form the tetrahydropyran ring.

Synthetic efforts towards the total synthesis of the revised structure of marine macrolide palmerolide C is reported. Synthesis of the triol unit present in the C8,C9, C10 positions was achieved from d -ribose while Johnson orthoester rearrangement and a Wittig reaction were used to construct the C1–C7 component of the macrolactone. The key macrolactone unit was assembled using intermolecular Heck coupling reaction and Yamaguchi lactonization.

Stereoselective synthesis of the C9-C22 fragment of pentamycin from the bis-Weinreb amide of d -tartaric acid was accomplished in 12 steps (14% yield). Key reactions in the synthesis include Ley’s dithiaketalization, Narasaka stereoselective reduction of the β-hydroxy ketone and Wittig reaction with a vinylogous phosphonate.

Desymmetrization of the C2-symmetric bis-dimethylamide derived from tartaric acid by controlled addition of alkynyl lithium reagents furnished the mono alkynyl ketones which on reduction produced the corresponding propargyl alcohols with good diastereoselectivity. The propargyl alcohols were transformed to allenes using Claisen rearrangement. The formed allenes serve as a precursor for the synthesis of one of the THP units of the natural product sorangicin and for the synthesis of the polyhydroxy unit present in natural product anamarine.

Formal total synthesis of (+)-stemoamide is accomplished from 5-benzyloxypentanal. Key transformation in the synthesis is the conjugate addition of aza-allylanion obtained from allyl amine to an unsaturated ester.

Enantioselective total synthesis of 2,4,6-trisubstituted pyran natural product diospongin A is accomplished from benzaldehyde in 5 steps. Key reaction in the synthesis is the addition of a silyl enol ether derived from vinylogous aryl methyl ketone to chiral β-alkoxy aldehyde and subsequent oxa-Michael addition.

Total synthesis of (+)-γ-lycorane is accomplished from (S)-ethyl lactate. Key disconnections in the synthesis involve an iterative Claisen and Overman rearrangement reactions to install the chiral centers in the tetrahydroindole moiety while, Pictet-Spengler reaction is used for the synthesis of the isoquinoline unit.

A facile ring opening of furans in furyl propargyl alcohols to the corresponding saturated gamma-keto esters is observed in the gold(III) chloride catalyzed reaction with MeOH. It is found that the ring opening of furan is driven by the intramolecular hydroalkoxylation. Mitigating the intramolecular hydroalkoxylation led to the expected conjugated enyne resulting from the dehydration. (C) 2015 Elsevier Ltd. All rights reserved.

Synthesis of β-sulfinamido ketones was accomplished by the addition of silyl enol ethers derived from arylmethyl ketones to chiral sulfinimines in excellent yield and selectivity. Application of the formed β-amino substituted ketones is exemplified in the total synthesis of sphingolipid HPA-12 and the sedamine alkaloids.

The enantioselective synthesis of the polyketide unit present in depsipeptides aetheramide A and B, which possess potent HIV-inhibitory activity, is accomplished from a chiral furyl carbinol.

A facile general route for the synthesis of azepino[4,5-b]indolones is presented. The strategy involves a Bronsted acid assisted intramolecular cyclization of unsaturated tryptamides. The methodology developed has been applied to the synthesis of the ABCD tetracyclic core of the natural product tronocarpine.

A novel ring contraction/rearrangement sequence leading to functionalized 2,8-oxymethano-bridged di- and triquinane compounds is observed in the reaction of various substituted 1-methyl-4-isopropenyl-6-oxabicylo[3.2.1]octan-8-ones with Lewis acids. The reaction is novel and is unprecedented for the synthesis of di- and triquinane frameworks.

The total synthesis of new indole alkaloids henrycinol A and B were accomplished starting from l -tryptophan methyl ester. The key step is a stereochemically flexible Pictet–Spengler reaction governed by the presence or absence of an N-allyl group in the tryptophan precursor. The natural products henrycinol A and B were synthesized in good overall yield in eight and nine steps, respectively.

An enantiospecific total synthesis of polyhydroxy δ-pyrone natural product (+)-anamarine is accomplished. The main features of the synthesis include the stereoselective reduction of the ketone obtained by the desymmetrization of the bis-dimethyl amide of tartaric acid and further elaboration involving asymmetric Brown's allylation and ring closing metathesis.

An enantioselective synthesis of the macrolactone core of natural product Sch725674 was accomplished from furfural. Key reactions in assembly of the macrolactone are the use of furan as a but-2-ene-dione equivalent and ring closing metathesis.

A systematic investigation of the addition of Grignard reagents to sulfinimines derived from tartaric acid diol was undertaken. It was observed that the chirality of the inherent tartrate moiety influences the diastereoselectivity of the resultant sulfinamides formed in the reaction. The formed products serve as excellent building blocks for the synthesis of natural products. This has been demonstrated in the collective total synthesis of lentiginosine, (+)-α-conhydrine and methyldihydropalustramate.

Chiral 2-pyridylsulfinamides were shown to be effective catalysts in the alkylation of aryl and alkyl aldehydes with diethylzinc providing the corresponding alcohols in excellent enantioselectivity. Sulfinamide catalysts possessing solitary chirality at the sulfur center produced the product phenethyl alcohol in good enantioselectivity. Diastereomeric sulfinamides possessing chirality at the carbon-bearing nitrogen and at the sulfur of the sulfinamide increased the enantioselectivity of the product alcohols up to >99%. However, there is no effect of the match-mismatch pair of sulfinamide diastereomers on the outcome of the chiral induction of the product phenethyl alcohols. It was conclusively proved that chirality at the sulfur center is mandatory for obtaining good enantioselectivity in the reaction.

Formation of a 2,3-dihydro-4H-pyran containing 14-membered macrocycle by sequential olefin cross metathesis and a highly regiospecific hetero Diels–Alder reaction was observed in the reaction of a hydroxydienone derived from tartaric acid with Grubbs' second generation catalyst. It was found that the free alcohol in the hydroxyenone led to the macrocycle formation, while protection of the hydroxy group formed the ring closing metathesis product.

An enantiospecific total synthesis of indole alkaloids eburnamonine, aspidospermidine and quebrachamine is described from lactic acid. Synthesis of all three alkaloids is accomplished from a single chiral building block. Johnson–Claisen rearrangement of a chiral allyl alcohol is the main feature for the installation of the required quaternary centre.

Synthesis of isochromanones and isoquinolones comprising a quaternary center with high diastereoselectivity was realized via a AuCl3 catalyzed tandem intramolecular exo-dig heterocyclization/enol isomerization/Claisen rearrangement sequence in excellent yields. The reaction is general and amenable for the synthesis of structurally diverse analogues.

A straightforward strategy for the synthesis of (+)-pinellic acid in 16% overall yield and 13 steps, starting from (1R)-1-(furan-2-yl)hexan-1-ol, is described. Key reactions in the synthesis include a Sharpless kinetic resolution, oxidation of a protected furan to reveal a but-2-ene-1,4-dione moiety, and an asymmetric reduction.

A concise and expeditious approach for the total synthesis of bioactive styryllactone (–)-crassalactone C is presented from tartaric acid. The main features of the synthesis include the desymmetrization of dimethylamide of tartaric acid and the effective use of cinnamoyl ester as a protecting group as well as a reactant in the ring-closing metathesis reaction.

Synthesis of the macrolactone depsipeptide aetheramide A was attempted by three different approaches. The first approach to form the macrolactone involving macrolactonization to form the C1-C21 bond and the second approach using a ring-closing metathesis (RCM) strategy to form the C10-C11 olefinic bond failed. The third approach starting from R-mandelic acid, involving the RCM reaction to install the C18-C19 ring junction, was successful in assembling the macrolactone.

Total synthesis of the polyhydroxy caprolactam amide natural product, bengamide E, is accomplished starting from tartaric acid. Key reactions in the synthesis include desymmetrization of the bis(dimethylamide) unit of tartaric acid, Zn(BH(4))(2)-mediated anti-selective reduction, and a Horner-Wadsworth-Emmons olefination.

An enantiospecific total synthesis of polyhydroxy δ-pyrone natural product phomopsolide B is accomplished. The main feature of the synthesis is the installation of the required E-olefin by Horner–Emmons–Wordsworth reaction and the formation of the lactone involving Still–Gennari olefination followed by lactonization.

A stereoselective total synthesis of (+)-cladospolide A from d -ribose is described. Key features of the synthesis include olefin cross metathesis and Yamaguchi lactonization.

The enantiospecific total synthesis of vinca alkaloid (+)-eburnamonine is accomplished from l -ethyl lactate. Key feature of the synthesis is the construction of the chiral quaternary center involving a Johnson–Claisen rearrangement and assembly of the pentacyclic core by the Pictet–Spengler reaction and ring-closing metathesis.