Replacement of Stoichiometric DDQ with a Low Potential o-Quinone Catalyst Enabling Aerobic Dehydrogenation of Tertiary Indolines in Pharmaceutical Intermediates
A transition-metal/quinone complex, [Ru(phd)3]2+ (phd = 1,10-phenanthroline-5,6-dione), is shown to be effective for aerobic dehydrogenation of 3° indolines to the corresponding indoles. The results show how low potential quinones may be tailored to provide a catalytic alternative to stoichiometric DDQ, due to their ability to mediate efficient substrate dehydrogenation while also being compatible with facile reoxidation by O2. The utility of the method is demonstrated in the synthesis of key intermediates to pharmaceutically important molecules.
Li, Bao,Wendlandt, Alison E.,Stahl, Shannon S.
supporting information
p. 1176 - 1181
(2019/02/14)
Novel approaches towards the LTD4/E4 antagonist, LY290154
Several novel approaches have been investigated for the synthesis of the LTD4/E4 antagonist LY290154. Significant improvements to the discovery route were first made by using an indoline nucleophile instead of an indolyl anion in the key substitution step. An alternative approach, introducing the 7-chloroquinoline moiety in the latest stages of the synthesis was then demonstrated. Interestingly, the pivotal intermediate of this latter route was also obtained in a one-pot process following a Katritzky methodology. Finally, an asymmetric synthesis offering significant advantages over the enantioselective route reported by McKillop was demonstrated.
A process for producing a compound of the formu5la STR1 comprising the step of reacting a compound of the formula STR2 with a compound of the formula STR3 to form a compound of the formula STR4 wherein R2a is selected from the groups recited ab
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(2008/06/13)
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