- Cobalt-Catalyzed Desymmetric Isomerization of Exocyclic Olefins
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Chiral cyclic olefins, 1-methylcyclohexenes, are versatile building blocks for the synthesis of pharmaceuticals and natural products. Despite the prevalence of these structural motifs, the development of efficient synthetic methods remains an unmet challenge. Herein we report a novel desymmetric isomerization of exocyclic olefins using a series of newly designed chiral cobalt catalysts, which enables a straightforward construction of chiral 1-methylcyclohexenes with diversified functionalities. The synthetic utility of this methodology is highlighted by a concise and enantioselective synthesis of a natural product, β-bisabolene. The versatility of the reaction products is further demonstrated by multifarious derivatizations.
- Lan, Yu,Liu, Qiang,Liu, Shihan,Liu, Xufang,Rong, Xianle
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p. 20633 - 20639
(2021/12/17)
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- Diastereoselectivity control of the radical carboazidation of substituted methylenecyclohexanes
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A systematic study of the diastereoselectivity of the radical carboazidation of methylenecyclohexane derivatives is presented. Several substitution patterns leading to a high level of stereocontrol have been identified. Axial attack is the preferred reaction pathway for cyclohexyl radicals, and excellent stereoselectivities can be obtained by introducing an axial substitutent at position 2. In this case, a second equatorial substituent at position 2 may be tolerated without a large detrimental effect on the diastereoselectivity. Finally, a high level of equatorial attack is observed with a very bulky substituent at position 2.
- Cren, Sylvaine,Schar, Pascal,Renaud, Philippe,Schenk, Kurt
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supporting information; experimental part
p. 2942 - 2946
(2009/09/06)
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