Gallium-mediated allyl transfer from bulky homoallyl alcohol to aldehydes or alkynes: Control of dynamic σ-allylgalliums based on retro-allylation reaction
reagent and gallium trichloride, bulky homoallylalcohols undergo gallium-mediated retro-allylation reaction to provide σ-allylgallium reagents. The σ-allylgallium reagents generated were applied to carbonyl allylation. The retro-allylation reaction generates (Z)- and (E)-σ-crotylgalliums stereospecifically, starting from erythro- and threo-homoallyl alcohols, respectively. The stereochemically defined
Ready Access to Benzannulated [5,5]-Oxaspirolactones Using Au(III)-Catalyzed Cascade Cyclizations
作者:Yash Mankad、Sagar S. Thorat、Pronay Das、Gamidi Rama Krishna、Ravindar Kontham、D. Srinivasa Reddy
DOI:10.1021/acs.joc.1c02843
日期:2022.3.4
showcases an unprecedented Au(III)-catalyzed cascade cyclization of 2-(4-hydroxyalkynyl)benzoates to access benzannulated [5,5]-oxaspirolactones related to biologically active natural products. This reaction proceeds through an initial 5-endo-dig mode of hydroalkoxylation of the alkynol segment to give the oxocarbenium species (via cyclic enol-ether) followed by the addition of carboxylate onto the oxocarbenium