Role of the methoxy group in product formation via TiCl4 promoted 4-phenyldioxolane isomerizationsons

Green, Ivan Robert; October, Natasha

doi:10.3998/ark.5550190.0011.206

Cited by 5 publications

(1 citation statement)

References 10 publications

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“…From a solution of syn -(±)- 7g (70.4 mg, 0.291 mmol) in DCM, ( E )-styrylboronic acid 8a (64.5 mg, 0.436 mmol), and In(OTf) 3 (326.6 mg, 0.581 mmol), following the general procedure, syn -(±)- 10g was obtained. Chromatographic purification (hexanes/EtOAc 10:1 to 1:1) provided syn -(±)- 10g (84.1 mg, 0.256 mmol, dr = 95:5) as a colorless oil.…”

Section: Methodsmentioning

confidence: 99%

Lewis Acid-Promoted Regio- and Diastereoselective Cross-Coupling of Aryl-Substituted 1,2-Diols and Boronic Acids

Lee

Kim

et al. 2019

J. Org. Chem.

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A Lewis acid-promoted highly regio- and diastereoselective C(sp3)–C(sp2) cross-coupling reaction between unprotected aryl-substituted 1,2-diols and styryl-, aryl-, heteroaryl-, and polyarylboronic acids has been developed in a one-pot procedure. The regioselective opening of aryl-substituted cyclic boronic esters promoted by a Lewis acid followed by subsequent intramolecular 1,4-transfer of the carbon ligand from boron to a resonance-stabilized benzylic carbenium ion minimizing the allylic 1,3-strain in a stereoselective fashion led to the corresponding α-substituted syn-phenylethyl alcohols. The synthetic utility of the method was illustrated by a short and efficient enantioselective synthesis of cherylline diethyl ether (−)-16.

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Section: Methodsmentioning

confidence: 99%

Lewis Acid-Promoted Regio- and Diastereoselective Cross-Coupling of Aryl-Substituted 1,2-Diols and Boronic Acids

Lee

Kim

et al. 2019

J. Org. Chem.

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Highly Selective and Potent Human β‐Secretase 2 (BACE2) Inhibitors against Type 2 Diabetes: Design, Synthesis, X‐ray Structure and Structure–Activity Relationship Studies

et al. 2019

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Herein we present the design, synthesis, and biological evaluation of potent and highly selective β‐secretase 2 (memapsin 1, beta‐site amyloid precursor protein cleaving enzyme 2, or BACE 2) inhibitors. BACE2 has been recognized as an exciting new target for type 2 diabetes. The X‐ray structure of BACE1 bound to inhibitor 2 a {N3‐[(1S,2R)‐1‐benzyl‐2‐hydroxy‐3‐[[(1S,2S)‐2‐hydroxy‐1‐(isobutylcarbamoyl)propyl]amino]propyl]‐5‐[methyl(methylsulfonyl)amino]‐N1‐[(1R)‐1‐phenylpropyl]benzene‐1,3‐dicarboxamide} containing a hydroxyethylamine isostere was determined. Based on this structure, a computational docking study was performed which led to inhibitor 2 a‐bound BACE2 models. These were used to optimize the potency and selectivity of inhibitors. A systematic structure–activity relationship study led to the identification of determinants of the inhibitors’ potency and selectivity toward the BACE2 enzyme. Inhibitors 2 d [N3‐[(1S,2R)‐1‐benzyl‐2‐hydroxy‐3‐[[(1S,2S)‐2‐hydroxy‐1‐(isobutylcarbamoyl)pentyl]amino]propyl]‐N1‐methyl‐N1‐[(1R)‐1‐phenylpropyl]benzene‐1,3‐dicarboxamide; Ki=0.031 nm, selectivity over BACE1: ≈174 000‐fold] and 3 l [N1‐((2S,3R)‐3‐hydroxy‐1‐phenyl‐4‐((3‐(trifluoromethyl)benzyl)amino)butan‐2‐yl)‐N3,5‐dimethyl‐N3‐((R)‐1‐phenylethyl)isophthalamide; Ki=1.6 nm, selectivity over BACE1: >500‐fold] displayed outstanding potency and selectivity. Inhibitor 3 l is nonpeptide in nature and may pave the way to the development of a new class of potent and selective BACE2 inhibitors with clinical potential.

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Synthesis of Oxacycles Employing the Oxa‐Pictet–Spengler Reaction: Recent Developments and New Prospects

2011

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The oxa‐Pictet–Spengler cyclization is the oxygen variation of the Pictet–Spengler reaction, in which an aromatic alcohol component (generally a β‐arylethyl alcohol) reacts with acarbonyl component (aldehyde, ketone or their masked derivatives), to yield a 1‐substituted (or 1,1′‐disubstituted)pyran fused to the aromatic ring system found in the starting alcohol. The transformation is usually promoted by Brønsted and Lewis acids. Intramolecular versions of the reaction are also known, where both components are mutually masked as an acetal. Discussed here are aspects concerning the most recent developments and new applications of this useful reaction, including the scope and limitations of new promoters, and new mechanistic pictures of this transformation. The use of novel stereochemical control strategies and the application of the reaction to the synthesis of natural products and their analogs, as well as to accessing fully synthetic bioactive compounds and new ring systems are presented, and chiral versions of the oxa‐Pictet–Spengler are also analyzed.

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Role of the methoxy group in product formation via TiCl4 promoted 4-phenyldioxolane isomerizationsons

Cited by 5 publications

References 10 publications

Lewis Acid-Promoted Regio- and Diastereoselective Cross-Coupling of Aryl-Substituted 1,2-Diols and Boronic Acids

Lewis Acid-Promoted Regio- and Diastereoselective Cross-Coupling of Aryl-Substituted 1,2-Diols and Boronic Acids

Highly Selective and Potent Human β‐Secretase 2 (BACE2) Inhibitors against Type 2 Diabetes: Design, Synthesis, X‐ray Structure and Structure–Activity Relationship Studies

Synthesis of Oxacycles Employing the Oxa‐Pictet–Spengler Reaction: Recent Developments and New Prospects

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