An interesting approach to transform the B ring of bryostatins to the C ring has been developed. The key tactics of the approach feature an intramolecular Csp3–H bond amination to form spirocyclic hemiaminal, which undergoes ring opening to afford the C ring found in bryostatin 17. The subsequent epoxidation/oxidation sequence results in Z to E isomerization of the exo-cyclic enoate, delivering the common precursor, which could be transformed into the C ring found in bryostatins 1, 2, 4–9, 12, 14, and 15.

An efficient approach to synthesize benzosiloline has been developed using a visible light-promoted radical cyclization reaction of silicon-tethered alkyl iodide and phenyl alkyne.

•(S)-(−)-Diphenylprolinol is shown as an efficient auxiliary to ensure the high diastereoselectivity of alkylation.•A range of optically pure chiral α-monosilyl amides were obtained in good yields with high diastereoselectivity.•The approach is applicable to synthesize sterically congested chiral α-bis(silyl) amides.Asymmetric alkylation or silylation of (S)-(−)-diphenylprolinol-derived α-silyl amide has been developed to synthesize optically pure α-monosilyl or bis(silyl) amides in good yields with high diastereoselectivity.

A regioselective 1,4-hydroiodination of dienyl alcohols has been developed using trimethylsilyl iodide as Lewis acid and iodide source. A range of homoallylic alcohols containing a multisubstituted Z-alkene was synthesized with good to excellent configurational control. The approach was applied in sequential hydroiodination/Prins cyclization to afford multisubstituted tetrahydropyrans diastereoselectively.

An efficient synthesis of functionalized γ-lactones has been developed involving Sakurai exo-cyclization/rearrangement of 3,3-bis(silyl) enol esters with a tethered acetal. While the steric and electronic effects of geminal bis(silane) favor the desired Sakurai pathway, the methoxy species formed in the deprotection step also facilitates both cyclization and rearrangement. The synthetic value of this approach has been demonstrated by efficiently transforming the E-vinylsilane into enyne and the γ-lactone moiety into multisubstituted THF.

The C–Si bond activation via a direct transition metal insertion has recently gained growing attention in the organic chemical community. The process not only shows a new and unique entry to functionalize the C–Si bond, but also presents a powerful method to synthesize diverse organosilanes via formation of a new C–Si bond. This Digest is intended to highlight some elegant advances, which are categorized into strained silacycles, acyclic C(sp3)–Si, acyclic C(sp2)–Si, and C(sp)–Si bond activation.

An efficient approach to synthesize benzosiloline has been developed using a visible light-promoted radical cyclization reaction of silicon-tethered alkyl iodide and phenyl alkyne.