Highly Stereoselective Anti SN2‘ Substitutions of (Z)-Allylic Pentafluorobenzoates with Polyfunctionalized Zinc−Copper Reagents
摘要:
[GRAPHICS]Allylic substitution reactions of zinc-copper organometallics on (Z)-allylic pentafluorobenzoates proceed with very high regioselectivity and excellent anti selectivity. The high fidelity in transfer of stereochemical information allowed a short synthesis of (+)-ibuprofen (97% ee).
Platinum catalysed hydrosilylation of propargylic alcohols
作者:Catherine A. McAdam、Mark G. McLaughlin、Adam J. S. Johnston、Jun Chen、Magnus W. Walter、Matthew J. Cook
DOI:10.1039/c3ob40496j
日期:——
A facile and user-friendly protocol has been developed for the selective synthesis of E-vinyl silanes derived from propargylicalcohols using a PtCl2/XPhos catalyst system. The reaction is generally high yielding and provides a single regioisomer at the β-position with E-alkene geometry. The reaction is extremely tolerant of functionality and has a wide scope of reactivity both in terms of alkynes
Rh(I)-Catalyzed Transformation of Propargyl Vinyl Ethers into (<i>E</i>,<i>Z</i>)-Dienals: Stereoelectronic Role of <i>trans</i> Effect in a Metal-Mediated Pericyclic Process and a Shift from Homogeneous to Heterogeneous Catalysis During a One-Pot Reaction
作者:Dinesh V. Vidhani、Marie E. Krafft、Igor V. Alabugin
DOI:10.1021/jo402505f
日期:2014.1.3
experiments and computations reveals unusual features of stereoselective Rh(I)-catalyzed transformation of propargyl vinylethers into (E,Z)-dienals. The first step, the conversion of propargyl vinylethers into allene aldehydes, proceeds under homogeneous conditions via a “cyclization-mediated” mechanism initiated by Rh(I) coordination at the alkyne. This path agrees well with the small experimental
Synthesis of Enantiopure Aliphatic Acetylene Alcohols and Determination of Their Absolute Configurations by1H NMR Anisotropy and/or X-ray Crystallography
Stereocontrolled Synthesis of (<i>E,Z</i>)-Dienals <i>via</i> Tandem Rh(I)-Catalyzed Rearrangement of Propargyl Vinyl Ethers
作者:Dinesh V. Vidhani、Marie E. Krafft、Igor V. Alabugin
DOI:10.1021/ol4019985
日期:2013.9.6
A novel Rh(I)-catalyzed approach to functionalized (E,Z) dienals has been developed viatandem transformation where a stereoselective hydrogen transfer follows a propargyl Claisen rearrangement. Z-Stereochemistry of the first double bond suggests the involvement of a six-membered cyclic intermediate whereas the E-stereochemistry of the second double bond stems from the subsequent protodemetalation
Alkynes were successfully converted into α,β-acetylenic carbonyl compounds through radical-catalyzed aerobic oxidation using N-hydroxyphthalimide (NHPI) combined with a transion metal under mild conditions.