Palladium-catalyzed allylic alkylation of tert-butyl(diphenylmethylene)-glycinate with simple allyl esters under chiral phase transfer conditions

Chen, Guoshu; Deng, Yijian; Gong, Liu‐Zhu; Mi, Aiqiao; Cui, Xin; Jiang, Yaozhong; Choi, Michael C. K.; Chan, Albert S. C.

doi:10.1016/s0957-4166(01)00276-2

Cited by 177 publications

(66 citation statements)

References 28 publications

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“…The GAL4 reporter plasmid UAS-TK-Luc contains two copies of the GAL4 recognition sequences upstream of TK109 in pA3Luc. Construction of nuclear receptor corepressor (NCoR), steroid receptor coactivator-1 (SRC-1), and RXR-␣ Gal4BD fusion expression vectors was described previously (37). The VP16AD-GS125 mutant TR-␤2 was created by exchanging appropriate restriction fragments within the VP16AD-TR-␤2 construct, which has been reported previously (38).…”

Section: Methodsmentioning

confidence: 99%

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Thyroid Hormone Receptor DNA Binding Is Required for Both Positive and Negative Gene Regulation

Shibusawa

Hollenberg

Wondisford

2003

Journal of Biological Chemistry

117

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The ␤ isoform of thyroid hormone receptor (TR-␤) has a key role in the feedback regulation of the hypothalamic-pituitary-thyroid (H-P-T) axis. The mechanism of trans-repression of the hypothalamic thyrotropin-releasing hormone (TRH) and pituitary thyroid-stimulating hormone (TSH) subunit genes, however, remains poorly understood. A number of distinct mechanisms for TR-␤-mediated negative regulation by thyroid hormone have been proposed, including those that require and do not require DNA binding. To clarify the importance of DNA binding in negative regulation, we constructed a DNA-binding mutant of TR-␤ in which two amino acids within the P box were altered (GSG for EGG) to resemble that found in the glucocorticoid receptor (GR). We termed this mutant GS125, and as expected, it displayed low binding affinities for positive and negative thyroid hormone-response element (pTRE and nTRE, respectively) in gel-mobility shift assays. In transient transfection assays, the GS125 mutant abolished transactivation on three classic pTREs (DR؉4, LAP, and PAL) and all negatively regulated promoters in the H-P-T axis (TRH, TSH-␤, and TSH-␣). However, GS125 TR-␤ bound to a composite TR/GR-response element and was fully functional on this hybrid TR/GR-response element. Moreover, the GS125 TR-␤ mutant displayed normal interactions with transcriptional cofactors in mammalian twohybrid assays. These data do not support a DNA-binding independent mechanism for thyroid hormone negative regulation in the H-P-T axis.The synthesis and secretion of thyroid hormones are exquisitely regulated by a negative feedback system that involves the hypothalamus, pituitary, and thyroid gland (the hypothalamicpituitary-thyroid axis: H-P-T axis). 1 The synthesis of thyrotropin-releasing hormone (TRH), produced in the paraventricular nucleus of the hypothalamus, and the ␣ and ␤ subunits of thyrotropin (thyroid-stimulating hormone; TSH) in the anterior lobe of the pituitary is inhibited at the transcriptional level by thyroid hormone (T 3 ) (1-4). Negative regulation of gene expression by T 3 is an integral part of the function in the H-P-T axis, and these effects are mediated by the ␤ isoform of the thyroid hormone receptors (TR-␤). Of the ␤ isoforms, TR-␤2 is quantitatively and functionally more important than TR-␤1 in regulating the hypothalamus and pituitary (5-8). The molecular mechanisms responsible for TR-mediated negative regulation of target genes are not well understood.In the traditional model of TR action, TR regulates gene expression by binding to specific thyroid hormone-response elements (TRE) on target genes. A number of artificial and natural positive thyroid hormone-response elements (pTREs) have been described, and they can be classified based on the half-site arrangement in the element: DRϩ4, PAL, and LAP (LYS) (9 -11). On target genes negatively regulated by T 3 , response elements (nTREs) have been described in the TRH and TSH-␤ subunit genes (12-17). In these nTREs, TR bound as a monomer to widely spaced half-sites or in the case of...

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Section: Methodsmentioning

confidence: 99%

“…Electrophoretic Mobility Shift Assay-The oligonucleotide sequences of DRϩ4 and TRH site 4 probe were reported previously (13,37). Hybrid TR/GR-response elements, TR/GRE 1, 2, and 3-DRϩ4 were designed to contain an intact 5Ј half-site and a mutant 3Ј half-site separated by a four-nucleotide gap.…”

Section: Methodsmentioning

confidence: 99%

Thyroid Hormone Receptor DNA Binding Is Required for Both Positive and Negative Gene Regulation

Shibusawa

Hollenberg

Wondisford

2003

Journal of Biological Chemistry

117

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“…Whereas c-Erb A binds N-CoR more strongly than SMRT (Cohen et al, 1998(Cohen et al, , 2000(Cohen et al, , 2001Webb et al, 2000;Makowski et al, 2003;Goodson et al, 2005;Zamir et al, 1997), we found that v-Erb A displayed a nearequal interaction with SMRT as with N-CoR. Restoring the c-Erb A helix 12 to v-Erb A restored the c-Erb A preference for N-CoR.…”

Section: Discussionmentioning

confidence: 63%

“…As anticipated, both v-Erb A SMRT corepressor is closely related to N-CoR but differs in its affinity for different nuclear receptors (Privalsky, 2004). Although alternative mRNA splicing can produce corepressors with differing receptor affinities, c-Erb A generally interacts more strongly with NCoR than with SMRT (Zamir et al, 1997;Cohen et al, 1998Cohen et al, , 2000Cohen et al, , 2001Webb et al, 2000;Makowski et al, 2003;Goodson et al, 2005). To examine this question for v-Erb A, we tested SMRT constructs in place of NCoR in our EMSA supershifts.…”

Section: Substitutions In the V-erb A I-box Enhance Homodimerization mentioning

confidence: 92%

“…V-Erb A displays an enhanced ability to bind to, and an altered preference for, corepressors compared to c-Erb A C-erb A homodimers recruit corepressor much more efficiently than do c-Erb A/RXR heterodimers (Cohen et al, 1998(Cohen et al, , 2000Yoh and Privalsky, 2001;Zubkova and Subauste, 2004). We inquired if this same preference of corepressor for homodimers was also true for v-Erb A.…”

Section: Substitutions In the V-erb A I-box Enhance Homodimerization mentioning

confidence: 99%

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Multiple mutations contribute to repression by the v-Erb A oncoprotein

Lee

Privalsky

2005

Oncogene

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Asymmetric CarbonCarbon Bond‐Forming Reactions

Chan

Helmchen

et al. 2010

Catalytic Asymmetric Synthesis

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The catalytic asymmetric conjugate addition to α , β -unsaturated compounds is one of the most powerful carbon -carbon and carbon -heteroatom bond -forming reactions in organic synthesis. The reaction is enormously useful for the construction of enantioenriched, highly functionalized carbon skeletons for the total syntheses of numerous biologically active compounds. The scope of the reaction is broad, owing to the availability of a large variety of donor and acceptor compounds. The high potential of this synthetic method is evident with the possibility of building multiple stereocenters in a single synthetic operation, and many asymmetric catalytic systems can exhibit high reactivity and stereoselectivity. In this chapter, recent advances in catalytic asymmetric conjugate addition reactions are described according to four categories: (i) conjugate addition of organometallics, (ii) conjugate addition of other carbon -centered nucleophiles, (iii) tandem conjugate addition reactions, and (iv) conjugate addition of heteroatom nucleophiles. 8A.2. CATALYTIC ASYMMETRIC CONJUGATE ADDITION OF ORGANOMETALLICSThe catalytic asymmetric conjugate addition of organometallic reagents to electrophilically activated olefi ns constitutes one of the most powerful methods for carbon -carbon Catalytic Asymmetric Synthesis, Third Edition, Edited by Iwao Ojima

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Palladium-catalyzed allylic alkylation of tert-butyl(diphenylmethylene)-glycinate with simple allyl esters under chiral phase transfer conditions

Cited by 177 publications

References 28 publications

Thyroid Hormone Receptor DNA Binding Is Required for Both Positive and Negative Gene Regulation

Thyroid Hormone Receptor DNA Binding Is Required for Both Positive and Negative Gene Regulation

Multiple mutations contribute to repression by the v-Erb A oncoprotein

Asymmetric CarbonCarbon Bond‐Forming Reactions

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