The Autoxidation of Quininone¹

Chemistry of Bridged Lactams and Related Heterocycles

“…60 At about the same time, R. B. Woodward attempted synthesis of related bicyclic 2-quinuclidones 31 (Scheme 1). 250 Although Woodward was unsuccessful in his studies, he also concluded that such compounds would represent a new type of aminoketone (see his comments to this effect in a footnote included in Doering’s paper, 251 discussed below).…”

Access to Highly Substituted 7-Azaindoles from 2-Fluoropyridines via 7-Azaindoline Intermediates

“…10 This pathway presumably occurs from the inherent instability of aldehydes 10 at elevated temperatures and the concomitant decarbonylation reaction by oxygen. 11 During our investigation, we also determined the Nef reaction to be incompatible with compounds bearing an aryl or heteroaryl We modified our strategy and targeted 7-azaindoles by way of their corresponding 7-azaindolines. 7-Azaindolines 6 were generated from ketones 9 or aldehydes 10 by reductive amination and in situ intramolecular S N Ar ring formation.…”

The Quest for Quinine: Those Who Won the Battles and Those Who Won the War

“…A previous sequence published in 1970 by Gates et al [155] (which was disclosed simultaneously with that of Gutzwiller and Uskokovic [153] ), also entailed the preparation of olefin 44 b; however, in this case phosphorane 43, which is derived from meroquinene alcohol, [156] and aromatic aldehyde 42 were employed in a Wittig reaction and the cis/trans mixture of olefins so obtained equilibrated with acetic acid to afford exclusively the more stable trans alkene (Scheme 13). Gates et al did not devise a protocol for the required construction of the alicyclic moiety, and considered his route explicitly as a partial synthesis of quinine.…”

“…[160] Enantiomerically pure meroquinene derivatives, were employed in the syntheses of Gates, Taylor, and that of Uskokovic (employing opening of the aminoepoxide); however, they were semisynthetically obtained by degradation of quinidinone. [156] Uskokovic et al disclosed their first synthesis of Nbenzoylmeroquinene (41 a) by a sequence vaguely reminiscent of Woodwards (Scheme 17) for his preparation of homomeroquinene (17). [160i,j] The cumbersome approach started with the catalytic hydrogenation of N-benzoylhexahydroisoquinolone (53), which provided a cis/trans mixture of octahydro derivatives in which the required cis diastereomer 53 a was favored.…”