61568-53-4Relevant articles and documents
Hauser-Heck: Efficient Synthesis of γ-Aryl-β-ketoesters en Route to Substituted Naphthalenes
Wagner, Frederic,Harms, Klaus,Koert, Ulrich
supporting information, p. 5670 - 5673 (2015/12/08)
γ-Aryl-β-ketoesters can be prepared in one step from aryl bromides and bis(trimethylsilyl) enol ethers using catalytic amounts of Pd(dba)2/t-Bu3P and stoichiometric amounts of Bu3SnF. The wide range of γ-(hetero)aryl-β-ketoesters that can be obtained illustrate the scope and limitations of this novel Hauser-Heck combination. γ-Aryl-β-ketoesters with a 1,3-dioxane acetal in the ortho position can easily be transformed into the hydroxy naphthoate in very good yield. Aqueous formic acid at 65 °C provides optimal conditions for this deprotective aromatization.
A synthetic route to highly substituted 1,2,3,4-tetrahydroisoquinolines via Yb(OTf)3-catalyzed diastereoselective ring opening of bridged oxazolidines: Asymmetric synthesis of 2-azapodophyllotoxin
Srivastava, Ajay Kumar,Koh, Minseob,Park, Seung Bum
supporting information; experimental part, p. 4905 - 4913 (2011/06/10)
We herein report a robust and efficient synthetic route to highly functionalized enantiopure 1,2,3,4-tetrahydroisoquinolines (THIQs) from Garner aldehyde. We utilized the inherent chirality of Garner aldehyde through 1,2- and 1,3-/1,4-asymmetric inductions iteratively to obtain 1,2,3,4-tetrasubstitued THIQs using rigid and isolable bridged oxazolidines without any external chiral sources. All possible stereoisomers of bridged oxazoliodines were efficiently synthesized from L- and D-Garner aldehydes and transformed into fully functionalized THIQs via diastereoselective ring opening with various nucleophiles in the presence of Yb(OTf)3. This methodology furnished four out of eight possible diastereomers of 1,2,3,4-tetrasubstituted THIQs despite the electronic nature of substituents on the aryl rings. Finally, the enantioselective synthesis of 2-azapodophyllotoxin was achieved with an overall yield of 35.4 % (eight steps) from D-Garner aldehyde using this synthetic route. A concise and efficient synthetic route to highly functionalized enantiopure 1,2,3,4-tetrahydroisoquinolines (THIQs) from the Garner aldehyde via Yb(OTf)3-catalyzed diastereoselective ring opening of bridged oxazolidines is reported. This methodology was successfully applied to the synthesis of four stereoisomers of THIQ and the enantioselective total synthesis of 2-azapodophyllotoxin (1) in eight steps from D-Garner aldehyde in an overall yield of 35.4 %. Copyright
Bismuth compounds in organic synthesis: Synthesis of dioxanes, dioxepines, and dioxolanes catalyzed by bismuth(III) triflate
Podgorski, Daniel M.,Krabbe, Scott W.,Le, Long N.,Sierszulski, Paul R.,Mohan, Ram S.
experimental part, p. 2771 - 2775 (2010/10/02)
A simple method for the synthesis of 1,3-dioxolanes from carbonyl compounds has been developed using 1,2-bis(trimethylsilyloxy)ethane in the presence of bismuth(III) triflate as a catalyst. The bismuth(III) triflate catalyzed synthesis of a range of dioxanes and dioxepines has also been developed. In these latter cases, the carbonyl compound is treated with a diol, and triethyl orthoformate is used as a water scavenger. All these methods avoid the use of a Dean-Stark trap. Georg Thieme Verlag Stuttgart.
