Enantioselective Lewis Acid Catalyzed ortho Photocycloaddition of Olefins to Phenanthrene-9-carboxaldehydes
Visible-light irradiation (λ=457 nm) enabled the enantioselective ortho photocycloaddition of olefins to phenanthrene-9-carboxaldehydes (15 examples, 46–93 % yield, 82–98 % ee). A chiral oxazaborolidine Lewis acid (20 mol %) was employed as the catalyst. It operates by coordination to the aldehyde inducing a bathochromic absorption shift beyond the nπ* absorption of the uncomplexed aldehyde. At long wavelengths the Lewis acid complex is exclusively excited; within the complex, one enantiotopic face of the aromatic aldehyde is efficiently shielded. Lewis acid coordination also alters the type selectivity and the simple diastereoselectivity of the photocycloaddition.
Chiral Magnesium Bisphosphate-Catalyzed Asymmetric Double C(sp3)-H Bond Functionalization Based on Sequential Hydride Shift/Cyclization Process
Described herein is a chiral magnesium bisphosphate-catalyzed asymmetric double C(sp3)-H bond functionalization triggered by a sequential hydride shift/cyclization process. This reaction consists of stereoselective domino C(sp3)-H bond functionalization: (1) a highly enantio- and diastereoselective C(sp3)-H bond functionalization by chiral magnesium bisphosphate (first [1,5]-hydride shift), and (2) a highly diastereoselective C(sp3)-H bond functionalization by an achiral catalyst (Yb(OTf)3, second [1,5]-hydride shift).
Regioisomerism in the synthesis of a chiral aminotetralin drug compound: Unraveling mechanistic details and diastereomer-specific in-depth NMR investigations
During chemical process development of a novel 2-aminotetralin derivative intended for use as an antidepressant, scrutiny of the byproduct present in the drug molecule revealed a set of regioisomers. Detailed studies showed that this impurity issue origin
Schuisky, Peter,Federsel, Hans-Juergen,Tian, Wei
experimental part
p. 5503 - 5514
(2012/09/07)
COMPOUNDS
The present invention relates to novel compounds, and therapeutically acceptable salts thereof of the formula (I), which inhibit exogenously or endogenously stimulated gastric acid secretion and thus can be used in the prevention and treatment of gastrointestinal inflammatory diseases
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(2019/03/15)
A new synthesis of 3-substituted-1H-indenes through reaction of o-(β-magnesioalkyl)phenylmagnesium dihalides with carboxylate esters
A new synthesis of 3-substituted-1H-indenes has been developed through the reaction of o-(β-magnesioalkyl)phenylmagnesium dihalides with carboxylate esters, followed by dehydration of the intermediate 1-substituted-1-indanols. Di-Grignard reagents allowing the synthesis of 3-substituted-, 2-methyl-3-substituted-, and 4-methyl-3-substituted-1H-indenes have been prepared, with overall yields for the two-step sequence ranging from 45 to 95%.
Baker, Robert W.,Foulkes, Michael A.,Griggs, Michael,Nguyen, Bao N.
p. 9319 - 9322
(2007/10/03)
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