216172-10-0Relevant articles and documents
One-pot practical preparation of novel propargylic aryl and heteroaryl sulfides and sulfones
Bonini, Carlo,Chiummiento, Lucia,Videtta, Valeria
, p. 3067 - 3070 (2005)
A one-pot preparation of functionalized propargylic aryl and hetero aryl sulfides from primary alcohols and thiols through the formation of the corresponding iodide or tosylate compounds is presented. The corresponding sulfones are prepared by subsequent
Rhodium-catalyzed hydroformylation of 1,1-disubstituted allenes employing the self-assembling 6-DPPon system
K?pfer, Alexander,Breit, Bernhard
supporting information, p. 6913 - 6917 (2015/06/08)
Abstract A rhodium-catalyzed hydroformylation of 1,1-disubstituted allenes is reported. Using a RhI/6-DPPon catalyst system, one can obtain β,γ-unsaturated aldehydes in high regio- and chemoselectivity. The Z-configured product is formed with up to >95% selectivity when unsymmetrically 1,1-disubstituted allenes are submitted to the reaction conditions. This is the first time that these interesting building blocks are accessible by hydroformylation of allenes. The utility of this methodology is demonstrated by further transformations of one of the obtained products. β,γ-Unsaturated aldehydes are obtained by a rhodium-catalyzed hydroformylation of 1,1-disubstituted allenes. For unsymmetrically 1,1-disubstituted allenes the Z-configured product is formed in up to about 95% selectivity. This is the first time that these building blocks are accessible by hydroformylation of allenes. The utility of this methodology is demonstrated by further transformations of one of the obtained products.
Amplification of anti-diastereoselectivity via Curtin-Hammett effects in ruthenium-catalyzed hydrohydroxyalkylation of 1,1-disubstituted allenes: Diastereoselective formation of all-carbon quaternary centers
Zbieg, Jason R.,Mclnturff, Emma L.,Leung, Joyce C.,Krische, Michael J.
supporting information; experimental part, p. 1141 - 1144 (2011/04/16)
Under the conditions of ruthenium-catalyzed transfer hydrogenation, 1,1-disubstituted allenes la-c and alcohols 2a-g engage in redox-triggered generation of allylruthenium-aldehyde pairs to form products of hydrohydroxyalkylation 3a-g, 4a-g, and 5a-g with complete branched regioselectivity. By exploiting Curtin-Hammett effects, good to excellent levels of anti-diastereoselectivity (4:1 to >20:1) are obtained. Thus, all carbon quaternary centers are formed in a diastereoselective fashion upon carbonyl addition from the alcohol oxidation level in the absence of premetalated nucleophiles or stoichiometric byproducts. Exposure of allene lb to equimolar quantities of alcohol 2a and aldehyde 6b under standard reaction conditions delivers adducts 4a and 4b in a 1:1 ratio. Similarly, exposure of allene lb to equimolar quantities of aldehyde 6a and alcohol 2b provides adducts 4a and 4b in an identical equimolar ratio. Exposure of allene lb to d2-p- nitrobenzyl alcohol, deuterio-2a, under standard reaction conditions delivers the product of hydrohydroxyalkylation, deuterioAa, which incorporates deuterium at the carbinol position (>95% 2H) and the interior vinylic position (34% H). Competition experiments involving exposure of allene lb to equimolar quantities of benzylic alcohols 2a and deuterio-2a reveal no significant kinetic effect. The collective data corroborate rapid, reversible alcohol dehydrogenation, allene hydrometalation, and (E)-, (Z)-isomerization of the transient allylruthenium in advance of turnover-limiting carbonyl addition. Notably, analogous allene-aldehyde reductive C-C couplings employing 2-propanol as the terminal reductant display poor levels of anti-diastereoselectivity, suggesting that carbonyl addition is not turnover-limiting in reactions conducted from the aldehyde oxidation level.
