13217-36-2Relevant academic research and scientific papers
Regio- and stereoselective Pd-catalyzed direct arylation of unactivated sp3 C(3)-H bonds of tetrahydrofuran and 1,4-benzodioxane systems
Parella, Ramarao,Babu, Srinivasarao Arulananda
, p. 2339 - 2355 (2015)
An auxiliary-enabled Pd-catalyzed highly regio- and stereoselective sp3 C-H activation and the direct arylation of the C3-position of oxygen heterocycles, such as tetrahydrofuran and 1,4-benzodioxane systems, are reported. An efficient stereoselective construction of cis 2,3-disubstituted tetrahydrofuran derivatives (analogues of norlignans) and cis 2,3-disubstituted 1,4-benzodioxane derivatives (analogues of neolignans) is described. The direct C(sp3)-H arylation of the C3-position of (R)- or (S)- tetrahydrofuran-2-carboxamides furnished the corresponding (2R,3R) and (2S,3S) C3-arylated THF scaffolds as major compounds with very high regio- and diastereoselectivities. The stereochemistry of the products obtained in this work were unambiguously assigned on the basis of the X-ray structure analyses of representative compounds 3b, 3e, 4p, and 7.
Palladium-Catalyzed Directed C(sp3)-H Arylation of Saturated Heterocycles at C-3 Using a Concise Optimization Approach
Affron, Dominic P.,Bull, James A.
, p. 139 - 149 (2016/01/20)
Saturated heterocycles, such as THFs, pyrrolidines, piperidines and THPs, are essential components of many biologically active compounds. Examples of C-H functionalization on these important ring systems remain scarce, especially at unactivated positions. Here we report the development of conditions for the palladium-catalyzed stereoselective C(sp3)-H arylation at unactivated 3-positions of 5- and 6-membered N- and O-heterocycles with aminoquinoline directing groups. Subtle differences in substrate structures altered their reactivity significantly; and different conditions were required to achieve high yields in each case. Successful conditions were developed using a short empirical optimization approach to cover reaction space with a limited set of variables. Excellent cis-selectivity was achieved in all cases, except for the THP substrate where minor trans-products were formed through a different palladacyclic intermediate. Here, differences in reactivity and selectivity with other directing groups were examined.
