The ortho-Claisen Rearrangement. IV. The Rearrangement of X-Cinnamyl p-Tolyl Ethers1
01 Sep 1961-Journal of the American Chemical Society (American Chemical Society)-Vol. 83, Iss: 18, pp 3846-3853
About: This article is published in Journal of the American Chemical Society.The article was published on 1961-09-01. It has received 42 citations till now. The article focuses on the topics: Claisen rearrangement.
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TL;DR: An unexpected N-heterocyclic carbene-catalyzed esterification of α,β-unsaturated aldehydes including aromatic aldeHydes with reactive cinnamyl bromides in the presence of air oxygen or MnO(2) as an oxidant is described.
Abstract: An unexpected N-heterocyclic carbene-catalyzed esterification of α,β-unsaturated aldehydes including aromatic aldehydes with reactive cinnamyl bromides in the presence of air oxygen or MnO2 as an oxidant is described. In the presence of oxygen, halogenated and electron-deficient aldehydes react smoothly to furnish esters in good yields. Great efforts have been made on mechanistic studies to deduce a plausible mechanism, based on the experimental results and isotopic labeling experiment.
99 citations
TL;DR: Two complementary strategies for the synthesis of the diazonamide A bisaryl quaternary center are described, which rely upon an extremely facile tandem cyclopropanation/ring-opening sequence and a more concise alkylation route ideal for material advancement.
80 citations
TL;DR: Tipranavir, an important antiviral agent in clinical development for the treatment of HIV, is synthesized in 15 linear steps from readily available starting materials in 25% overall yield by utilizing Pd- and Mo-catalyzed DYKAT reactions to control the quaternary and tertiary stereogenic centers, respectively.
Abstract: Tipranavir, an important antiviral agent in clinical development for the treatment of HIV, is synthesized in 15 linear steps from readily available starting materials in 25% overall yield by utilizing Pd- and Mo-catalyzed DYKAT reactions to control the quaternary and tertiary stereogenic centers, respectively.
76 citations
TL;DR: In this article, structural features of metallocene derivatives in which a carbenium ion center is connected adjacent to a cyclopentadienyl ring η-bound to a transition metal are collected.
75 citations
TL;DR: In this article, three ruthenium complexes that bear π-bound nitrogen heterocycles have been synthesized, and it is established that these complexes serve as effective nucleophilic catalysts for a range of processes, including the acylation of alcohols with diketene and the ring opening of azlactones.
Abstract: Three ruthenium complexes that bear π-bound nitrogen heterocycles have been synthesized. It is established that these complexes serve as effective nucleophilic catalysts for a range of processes, including the acylation of alcohols with diketene, the ring opening of azlactones, and the addition of alcohols to ketenes; their activity is comparable to or somewhat greater than the corresponding iron catalysts. The relative efficiency of the ruthenium complexes as asymmetric catalysts is also evaluated: in the kinetic resolution of secondary alcohols, ruthenium is markedly less effective than iron, but in the deracemization/ring opening of azlactones, ruthenium is slightly more enantioselective. This study documents for the first time the impact of the metal on the reactivity and on the enantioselectivity of nucleophilic catalysts based on π-bound nitrogen heterocycles.
75 citations