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A stable and easily prepared catalyst for the enantioselective reduction of ketones. Applications to multistep syntheses
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In this paper, the authors described a new method for the catalytic enantioselective reduction of ketones to chiral secondary alcohols, where the stoichiometric reagent in the reduction is borane and the catalyst is a chiral oxazaborolidine such as 1 (0.05-0.1 molfmol of ketone).Abstract:
We have recently described a new method for the catalytic enantioselective reduction of ketones to chiral secondary alcohols.' The stoichiometric reagent in the reduction is borane (usually 0.6 molfmol of ketone), and the catalyst is a chiral oxazaborolidine such as 1 (0.05-0.1 molfmol of ketone). Excellent enantioselectivities, easy recoverability of the chiral catalyst predecessor, near quantitative yields, short reaction times (a few minutes at 23 \"C), and predictability of the absolute configuration of the product contribute to the outstanding utility of this (CBS') process. This paper reports several subsequent developments in this area with respect to improved practicality and important applications. In contrast to 1 which is both air and moisture sensitive, the B-methylated oxazaborolidine 2 can be stored in closed containers at room temperature and weighed or transferred in air. Catalyst 2 is also much more easily prepared than 1. Reaction of (S)-read more
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cis-1-Amino-1,2,3,4-tetrahydro-2-naphthalenol: resolution and application to the catalytic enantioselective reduction of ketones
TL;DR: In this paper, -1-amino-1,2,3,4,4-tetrahydro-2-naphthalenol was synthesized and resolved via its diastereomeric salts.
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Synthesis of the C‐8–C‐24 Fragment of Maltepolide C by Using a Tandem Dihydroxylation/SN2 Cyclization Sequence
TL;DR: A highly stereoselective synthesis of the C-8–C-24 fragment of maltepolide C has been achieved in a convergent and efficient manner by utilizing a tandem Sharpless asymmetric dihydroxylation (SAD)/SN2 cyclization reaction sequence as the key step.
Journal ArticleDOI
Synthesis of Oxa-B-Ring Analogs of Colchicine through Rh-Catalyzed Intramolecular [5+2] Cycloaddition
Andreas Ole Termath,Stefanie Ritter,Marcel König,Darius P. Kranz,Jörg-Martin Neudörfl,Aram Prokop,Hans-Günther Schmalz +6 more
TL;DR: While compounds 3 and 24 did not exhibit noteworthy cytotoxic activity by themselves, they were found to strongly enhance the cytostatic activity of doxorubicin against resistant Nalm-6 cells (i.e., in a synergy effect).
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β-Hydroxyamide derivatives of salicylic acid as organocatalysts for enantioselective reductions of prochiral ketones
TL;DR: In this article, a series of β-hydroxyamide derivatives of salicylic acid and chiral amino alcohols were synthesized for the enantioselective reduction of a prochiral ketone.
Journal ArticleDOI
Sensitivity of substitution to the extent of self-immolative chirality transfer during reaction cascades originating from squarate esters
TL;DR: In this paper, reaction cascades induced by the addition to diisopropyl squarate of at least one cycloalkenyl anion possessing an oxygenated leaving group have been examined for the purpose of evaluating the level of chirality transferred to several new stereogenic centers as the original one is destroyed through β-elimination.
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Book
Molybdenum and Molybdenum-Containing Enzymes
TL;DR: In this article, a few moment to read a book even only few pages is recommended, even if it is not obligation and force for everybody, reading book becomes a choice of your different characteristics.
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