Effects of substitution on intramolecular alkoxypalladation carbonylation reactions

Intramolecular Palladium(II)-Mediated Alkoxy Carbonylation as a Route to Functionalized Tetrahydropyrans. Synthesis of the C9−C32 Segment of Phorboxazole A

“…It was further shown that 2,6-disubstituted tetrahydropyrans are generated exclusively with cis configuration in this process. Our observations followed upon earlier results of Semmelhack and Liotta, whose studies focused on the application of intramolecular alkoxy carbonylation to the synthesis of tetrahydrofurans. We have recently extended this methodology to the synthesis of tetrahydropyrans of greater stereochemical complexity, and we now wish to describe its application to the stereocontrolled assembly of a segment of phorboxazole A 5,6 that includes two of the four tetrahydropyrans, B and C, of this structure.…”

C−C, C−O, C−N Bond Formation on sp2 Carbon by Pd(II)-Catalyzed Reactions Involving Oxidant Agents

“…The effect of alkene geometry on the selectivity between five- or six-membered rings formation was studied by Semmelhack and co-workers (Scheme ). While E -isomer 254 mainly gave pyran 255 , Z -isomer 256 afforded furan 257 as the predominant products when catalytic PdCl 2 and a stoichiometric amount of CuCl 2 were used in methanol as solvent at room temperature under 1.1 atm of CO 186 …”

The syn/anti‐Dichotomy in the Palladium‐Catalyzed Addition of Nucleophiles to Alkenes

“…Several other examples followed shortly, all featuring the initial anti -addition of the electrophilic Pd II and the neighboring OH group across the C=C bond,[37–39] such as the cyclization of 71 and 73 (Scheme 22),[39] and 76 (Scheme 23), followed by carbonylation, as detailed in the previous paragraph. [3a]…”