A tandem oxidativecouplingreaction of β-ketoallenes and arenes was developed, which leads to the formation of 2-furylmethylarenes using AuCl3 and phenyliodine diacetate. The AuIII salt catalyzed the cyclization of β-ketoallenes to form a 2-furylmethyl gold intermediate, and the subsequent C–H functionalization of arenes proceeded smoothly. During the oxidativecoupling, nucleophilic additions occurred
demonstrated a very generalmethod for the preparation of essentially any terminal 2,3-allenol from the corresponding alkynols, which may be easily available from propargylic alcohols by alkylation, or from terminal alkynes by deprotonation and 1,2-addition with aldehydes or ketones, and subsequent base-catalyzed triple-bond migration. We have demonstrated a very generalmethod for the preparation of essentially
Palladium-Catalyzed Stereoselective Cyclization of <i>in Situ</i> Formed Allenyl Hemiacetals: Synthesis of Rosuvastatin and Pitavastatin
作者:Pierre A. Spreider、Bernhard Breit
DOI:10.1021/acs.orglett.8b01156
日期:2018.6.1
A diastereoselective palladium-catalyzed cyclization of allenyl hemiacetals is described. It permits the selective synthesis of 1,3-dioxane derivatives, precursors for syn-configured 1,3-diols which make an appearance in all of the statin representatives. The reaction allows the total synthesis of Rosuvastatin and Pitavastatin in a straightforward fashion.
Addition of Chloroprene Grignards to Aromatic Aldehydes: Synthesis of Homoallenyl Alcohols
作者:Arne G. A. Geissler、Bernhard Breit
DOI:10.1021/acs.orglett.1c00527
日期:2021.4.2
A general procedure for the one-pot synthesis of racemic homoallenyl alcohols from the corresponding aldehyde and chloroprene-derived Grignards is described. Employing bis[2-dimethylaminoethyl]ether (BDMAEE) as an additive at low temperatures shifts the selectivity of the chloroprene Grignard addition to aldehydes such that it is almost exclusive toward allene formation. In a set of follow-up experiments
Diastereofacial selectivity in Diels-Alder reactions of chiral 2-substituted-1,3-dienes.
作者:Robert Bloch、Nathalie Chaptal-Gradoz
DOI:10.1016/s0040-4039(00)60028-x
日期:1992.10
described. Thermal Diels-Alderreactions between these dienols or their ethers 3 and various dienophiles give rise with fair to good regio- and diastereoselectivity to monocyclic “para” adducts. In contrast a total regioselectivity and an excellent π-facial selectivity is observed when the Diels-Alder cycloadditions of the dienic ethers 3 are conducted in the presence of a Lewis acid.