Chirality exchange benzannulation of optically active (1S)-aryl(aryl')-2,2-dichlorocyclopropylmethanols (>99% ee) using TiCl4 successfully proceeded to give axially chiral (M)-alpha-arylnaphthalenes with excellent levels stereo induction ee). This unique transformation involves the single-step chirality from sp3 central axial chirality, that is, a type memory effect.

Abstract We have developed an efficient method for the esterification or thioesterification of equimolar amounts carboxylic acids and alcohols thiols using a novel reagent, p ‐toluenesulfonyl chloride (TsCl) together with N ‐methylimidazole. The present is simple, mild, reactive, uses readily available economical reagents. choice amine critical method. amine, ‐methylimidazole, has two roles: (i) as HCl scavenger initial smooth generation mixed anhydrides between TsCl (ii) successive...

An efficient synthesis of highly substituted α-arylnaphthalene analogues has been developed utilizing Lewis acid-promoted regiocontrolled benzannulation aryl(aryl')-2,2-dichlorocyclopropylmethanols (aryl ≠ aryl'; abbreviated as AACMs). Both AACM diastereomers were easily prepared via stereoselective addition (>95/5) ArLi to gem-dichlorocyclopropropyl aryl' ketones. The choice acids determined the cyclization regioselectivity present benzannulation. TiCl4 and SnCl4 used chelation pathway,...

Abstract The first total synthesis of three (+)-podophyllic aldehydes was achieved in a highly enantiocontrolled manner. Key steps include the organocatalyzed enantioselective cyclopropanation and Lewis acid-mediated chiral transfer ring expansion with excellent level stereoinduction. This method can alternatively provide (+)- (−)-podophyllic by switching organocatalyst asymmetric cyclopropanation.

We have developed an efficient method for the preparation of enol silyl ethers using novel agents, silazanes together with NaH or DBU catalyst, wherein TMS and TBDMS groups were smoothly chemoselectively introduced into ketones aldehydes under mild conditions.

In our previous study, we reported that the administration of T4 to patients with Graves' disease who were under treatment methimazole (MMI) decreased level antibodies thyroid-stimulating hormone (TSH) receptors and rate recurrence hyperthyroidism. this effect on postpartum hyperthyroidism was examined. Seventy-eight had been treated MMI for 1-3 yr before pregnancy, discontinued 5-6 months after onset pregnancy because levels TSH during early pregnancy. The then divided into two groups....

Multi-substituted <italic>trans</italic>-dihydronaphthalenes were obtained in high ee from a TiCl₄-mediated cyclization of enantioenriched D–A cyclopropanes, followed by triflation OH.

Abstract A novel ring-expansion of methyl (arylhydroxymethyl)cyclopropanecarboxylates 1 using Sc(OTf)3 or BF3·OEt2 afforded 1,2-dihydronaphthalene-3-carboxylic acid ester 2 in high to excellent yields. In the reaction, highly regioselective ring opening cyclopropane and sequential cyclization occurred.

Acid treatment of two types aryl(gem-dihalogenocyclopropyl)methanols (ADCMs) 1 and 3 gives α- β-halogenonaphthalenes in good yields with excellent selectivity. These alternative annulations involve distinctive highly regioselective acid-induced cyclopropane ring cleavage, wherein the preferential formation more stable cationic intermediates determines The stereochemical mode both preparation annulation between diastereoisomers an ADCM has been checked. As a demonstration this annulation,...

TiCl4–Bu3N-mediated condensation of ketones with α,α-dimethoxyketones afforded trialkylsubstituted 2(5H)-furanones in a one-pot manner, wherein aldol addition and furanone formation occurred sequentially; its application to straightforward synthesis (R)-mintlactone (R)-menthofuran, two representative natural mint perfumes, is demonstrated.

Cytosolic NADPH-dependent 3,5,3'-triiodo-L-thyronine (T3)-binding protein (CTBP) purified from rat kidney was further characterized in its T3 binding and interaction with nuclei. Pretreatment of the CTBP NADP induced dithiothreitol (DTT)-dependent binding. The DTT-dependent increased by a concentration-dependent manner, maximal obtained 0.1 microM NADP. Higher concentrations (more than microM), however, reduced NAD also binding, but very low compared to that NADPH NADH did not produce This...

The NADPH-dependent cytosolic 3,5,3'-triiodo-L-thyronine(T3)-binding protein (CTBP) has been purified over 30,000-fold from rat kidney by using charcoal extraction, Mono Q-Sepharose, Blue Sepharose CL-6B, and Sephacryl S-200 column chromatography. Purified CTBP had a sedimentation coefficient of 4.7 S, Stokes radius 32.5A, calculated molecular weight 58,000. apparently homogeneous consisted single polypeptide chain with Mr 58,000 as estimated sodium dodecyl sulfate-polyacrylamide gel...

In the presence of HMPA in THF, highly stereoselective SmI(2)-promoted substitutions alkyl 1-chlorocyclopropanecarboxylates 1 using various ketones, aldehydes (Reformatsky-type reaction), and acyl chlorides (acylation) proceeded to give trans-adducts (2 or 5) good high yield with excellent trans-stereoselectivity (trans-add/cis-add = > 99/1). The Reformatsky-type reaction unsymmetrical ketones moderate diastereoselectivity (re-face-adduct/si-face-adduct 60/40-75/25).

22-Oxa-1,25-dihydroxyvitamin D3 (oxacalcitriol, or OCT) is a bioactive analogue of 1 alpha,25-dihydroxyvitamin [1,25(OH)2D3] with lower calcemic activity than the parent compound. We investigated ability OCT to stimulate 1) genomic pathways mediated by nuclear receptors for 1,25(OH)2D3 versus 2) nongenomic voltage-sensitive Ca2+ channels in growth phase rat osteosarcoma cells (ROS 17/2.8) and chick intestine. Effects on receptor-mediated were evaluated measuring compete [3H]1,25(OH)2D3...

Reactions of gem-dichlorocyclopropanes with MeMgBr or t-BuMgCl were examined in the presence Fe, Co, and Ni (group VIIIA, first transition series) catalysts. The Fe(dbm)3 catalyst promoted dimethylations 4-methoxytoluene p-xylene. In contrast, CoCl2(dppe) conducted their hydrodechlorination.

A couple of radical carbonylations gem-dihalocyclopropanes 1 using CO and Bu3SnH (formylation) or Bu3Sn(CH2CH=CH2) (allylacylation) successfully proceeded to give trans cis adducts (2 3) with good excellent stereoselectivity (trans/cis = >99/1-75/25 17/83-1/99). The formylation 2,3-cis-disubstituted 1,1-dihalocyclopropanes enhanced selectivity >99/1-95/5), whereas both 2-monosubstituted underwent allylacylation nearly complete >99/1). Inherently less reactive gem-dichloro-...

Abstract Highly stereoselective SmI2-promoted substitutions of alkyl 1-chlorocyclopropanecarboxylate 1 using TMSCl or halide proceeded to give trans adduct 2 3 in moderate high yield with excellent stereoselectivity (trans-add/cis-add = &amp;gt;99/1) the presence HMPA THF. Silylation occurred on α-carbon ester regio- and (C-silylation/O-silylation &amp;gt;99/1, trans-add/cis-add &amp;gt;99/1).

The hydrogenolysis of enantioenriched donor–acceptor ( D–A ) cyclopropanes using H 2 (1 atm) and a catalytic amount palladium on charcoal gave trans ‐α‐alkoxycarbonyl‐β‐benzyl‐γ‐lactones or β‐substituted γ‐aryl‐α,α‐diesters with high enantiomeric excess. reaction was also used as key step in the asymmetric total synthesis yatein ee excellent dr . This demonstrates utility this new protocol for ‐α,β‐disubstituted γ‐butyrolactones. containing electron‐withdrawing groups at β‐position were not...

Abstract A highly regioselective and stereoselective 1,5‐addition of alkyl groups to enantioenriched donor–acceptor cyclopropanes 1 bicyclic such as 6‐aryl‐1‐methoxycarbonyl‐3‐oxabicyclo[3.1.0]hexan‐2‐ones 4 using a Grignard reagent with catalytic amount Cu(OTf) 2 (0.1 equivalent) afforded optically active diesters or trans ‐α,β‐disubstituted γ‐butyrolactones 5 an excellent level stereoinduction. An excess the is necessary perform 1,5‐alkylation high yields. In reaction lactone , subsequent...