10.1021/acs.orglett.7b01513.s001 Younes Fegheh-Hassanpour Younes Fegheh-Hassanpour Tanzeel Arif Tanzeel Arif Herman O. Sintim Herman O. Sintim Hamad H. Al Mamari Hamad H. Al Mamari David M. Hodgson David M. Hodgson Synthesis of (−)-6,7-Dideoxysqualestatin H5 by Carbonyl Ylide Cycloaddition–Rearrangement and Cross-electrophile Coupling American Chemical Society 2017 hydrazone diazo functionality Csp facilitation co-generation cross-electrophile β- hydroxy -α-ketoester motif Rh tartrate acetonide enolate Ylide Cross-electrophile alkylation synthesis stereoretentive oxidation diastereoselective n tricarboxylate core ylide formation dideoxysqualestatin Dideoxysqualestatin Key features Ni-catalyzed carbonyl entry cyclic Carbonyl ozonolysi side chain Synthesi Cycloaddition 2017-06-19 23:03:42 Journal contribution https://acs.figshare.com/articles/journal_contribution/Synthesis_of_-6_7-Dideoxysqualestatin_H5_by_Carbonyl_Ylide_Cycloaddition_Rearrangement_and_Cross-electrophile_Coupling/5119996 An asymmetric synthesis of (−)-6,7-dideoxysqualestatin H5 is reported. Key features of the synthesis include the following: (1) highly diastereoselective <i>n</i>-alkylation of a tartrate acetonide enolate and subsequent oxidation–hydrolysis to provide an asymmetric entry to a β-hydroxy-α-ketoester motif; (2) facilitation of Rh­(II)-catalyzed cyclic carbonyl ylide formation–cycloaddition by co-generation of keto and diazo functionality through ozonolysis of an unsaturated hydrazone; and (3) stereoretentive Ni-catalyzed Csp<sup>3</sup>–Csp<sup>2</sup> cross-electrophile coupling between tricarboxylate core and unsaturated side chain to complete the natural product.