Chiral Macrocycle-Catalyzed Highly Enantioselective Phenylacetylene Addition to Aliphatic and Vinyl Aldehydes
作者:Zi-Bo Li、Tian-Dong Liu、Lin Pu
DOI:10.1021/jo070091j
日期:2007.6.1
The 1,1‘-binaphthyl macrocycle (S)-2 is found to be an excellent catalyst for the alkyne addition to aldehydes. In the presence of (S)-2 (20 mol %) and Me2Zn (2 equiv) in THF at room temperature, the addition of phenylacetylene to linear or branched aliphatic aldehydes and vinylaldehydes gave various propargylic alcohols with 89−96% ee.
Highly regioselective gold-catalyzed formal hydration of propargylic <i>gem</i>-difluorides
作者:Jean-Denys Hamel、Tatsuru Hayashi、Mélissa Cloutier、Paul R. Savoie、Olivier Thibeault、Meggan Beaudoin、Jean-François Paquin
DOI:10.1039/c7ob02406a
日期:——
Herein, we report a highlyregioselective gold-catalyzed formal hydration of propargylic gem-difluorides. Not only does this transformation provide access to versatile fluorinated building blocks that were difficult or hardly possible to access beforehand, but it also represents a rare case of a highlyregioselective gold-catalyzed hydroalkoxylation of internal alkynes and puts forward the utility
Asymmetric transfer hydrogenation of unsaturated ketones; factors influencing 1,4- vs 1,2- regio- and enantioselectivity, and alkene vs alkyne directing effects
作者:Thomas H. Hall、Hannah Adams、Vijyesh K. Vyas、K.L. Michael Chu、Martin Wills
DOI:10.1016/j.tet.2020.131771
日期:2021.1
A detailed study has been completed on the asymmetric transferhydrogenation (ATH) of a series of enones using Ru(II) catalysts. Electron-rich rings adjacent to the CO group reduce the level of CO reduction compared to CC. The ATH reaction can readily discriminate between double and triple bonds adjacent to ketones, reducing the double bond but leaving a triple bond intact in the major product.
Highly Enantioselective Phenylacetylene Additions to Both Aliphatic and Aromatic Aldehydes
作者:Ge Gao、David Moore、Ru-Gang Xie、Lin Pu
DOI:10.1021/ol026921r
日期:2002.11.1
The readilyavailable and inexpensive BINOL in combination with Ti(O(i)Pr)(4) is found to catalyze the reaction of an alkynylzinc reagent with various types of aldehydes including aliphaticaldehydes, aromaticaldehydes, and other alpha,beta-unsaturated aldehydes to generate chiral propargyl alcohols with 91-99% ee at room temperature. No previous chiral catalysts have exhibited such a broad scope
A new tandem allylation/enyne cycloisomerization reaction was developed to construct densely functionalized oxygen hetereocycles with high diastereoselectivities from the intermolecular reaction of allylic acetates with propargylic alcohols via gold catalysis. Terminal and nonterminal propargylic alcohols take different reaction routes either to provide 3-oxa-bicyclo[4.1.0]hept-4-ene derivatives 5