We addressed an unexplored application of the Suzuki-Miyaura protocol to the cross-coupling of 1,1-dichloro-1-alkenes with 9-alkyl-9-BBN. The use of bisphosphine ligands with a large P-Pd-P bite angle allowed us to synthesize Z-chlorinated internal alkenes in good yields resulting from a selective monocoupling process, a recurrent challenge with 1,1-dichloro-1-alkenes. Moreover, these monochlorinated olefins could be further transformed providing stereospecifically trisubstituted olefins.

Two sensitive fragments were coupled in the mild title reaction to create the Z‐chlorovinyl functionality of the target macrolide oocydin A (1; see scheme). Another highlight in the total synthesis of 1 was an efficient stereoselective Pd0‐catalyzed cyclization to form the highly substituted tetrahydrofuran ring. Bz=benzoyl, TBS=tert‐butyldimethylsilyl, MPM=4‐methoxyphenylmethyl.

Tiacumicin B is an antibiotic endowed with the remarkable ability to interact with a new biological target, giving it an inestimable potential in the context of the ever-growing and worrisome appearance of resistances of bacteria and mycobacteria to antibiotics. The synthesis of an aglycone of tiacumicin B ready for glycosylation is reported. The key steps of this approach are a [2,3]-Wittig rearrangement, a Pd/Cu-catalyzed allene-alkyne cross-coupling, a E-selective cross-metathesis, and a final ring-size selective macrolactonization.

Hydrogen bonds can play a prominent role in organometallic catalysis, as shown for the title reaction, in which a counteranion directs the cyclization through the formation of hydrogen bonds that likely involve a proton of the π-allyl/palladium species itself. The reaction allows access to four out of the eight stereoisomers of 2,5-disubstitued 3-hydroxy-tetrahydrofurans and thus fragments of complex natural products.

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A concise total synthesis of the very promising antiproliferative macrolide (+)-neopeltolide (1) has been performed in 16 steps. The main steps of this approach are a Ru(II)-catalyzed alkyne-enal coupling, a Pd0-catalyzed desulfurative cross-coupling, and a stereoselective In(III)-catalyzed propargylation. Four stereogenic centers out of six have been set thanks to substrate-controlled diastereoselective reactions with minimal reliance on protecting groups.

A total synthesis of tiacumicin B, a natural macrolide whose remarkable antibiotic properties are used to treat severe intestinal infections, is reported. The strategy is in part based on the prior synthesis of the tiacumicin B aglycone, and on the decisive use of sulfoxides as anomeric leaving groups in hydrogen‐bond‐mediated aglycone delivery (HAD). This new HAD variant permitted highly β‐selective rhamnosylation and noviosylation. To increase convergence, the rhamnosylated C1–C3 fragment thus obtained was anchored to the C4–C19 aglycone fragment by adapting the Suzuki–Miyaura cross‐coupling used for the aglycone synthesis. Ring‐size‐selective macrolactonization provided a compound engaged directly in the noviolysation step with virtually total β selectivity. The final efficient removal of all the protecting groups provided synthetic tiacumicin B.

[reaction: see text]. A short and efficient asymmetric synthesis of the C12-C19 fragment of the cytotoxic macrolide (+)-peloruside A has been achieved via a highly diastereomer-discriminating RCM of alpha-branched but-3-enoate ester of a methallylic alcohol derived from hydrolytically resolved (S)-(-)-propylene oxide.