Synthesis of 1,4-cyclohexadienes
The cobalt-catalyzed Diels-Alder reaction of alkynyl pinacol boronic esters with various dienes generates cycloadducts in very good regioselectivity. A reaction sequence (Diels-Alder reaction, Suzuki coupling, DDQ oxidation) was successfully performed as a one pot operation without isolation of the intermediates.
G. Hilt, K. I. Smolko, Angew. Chem. Int. Ed., 2003, 42, 2795-2797.
Aryne Diels-Alder reactions with functionalized acyclic dienes give useful cis-substituted dihydronaphthalene building blocks in good yield. Asymmetric aryne cycloadditions with Oppolzer's sultam as a chiral auxiliary are also reported .
C. Dockendorff, S. Sahli, M. Olsen, L. Milhau, M. Lautens, J. Am. Chem. Soc., 2005, 127, 15028-15029.
The use of bench-stable sodium dispersions and recoverable 15-crown-5 ether enables a significantly improved, practical, and chemoselective ammonia-free Birch reduction of a broad range of aromatic and heteroaromatic compounds in excellent yields.
P. Lei, Y. Ding, X. Zhang, A. Adijiang, H. Li, Y. Ling, J. An, Org. Lett., 2018, 20, 3439-3442.