The cover picture shows a direct synthesis of 26-thio steroidal sapogenins from natural steroidal sapogenins, which serve as an important kind of resource compounds and basic starting materials in steroidal pharmaceutical industry. This method was based on a key and magic BF₃·Et₂O promoted C-26 sulfuration of steroidal sapogenins, which resulted in the direct replacement of the oxygen atom in F-ring of steroidal sapogenins by sulfur. The synthesis not only provides a concise method for 26-thio steroidal sapogenins, but also presents an ideal model of the utilization of steroidal sapogenins. More details are discussed in the article by Wang and Tian et al. on page 632–636.

A synthesis of tribolure, which divided the four stereoisomers of tribolure into two sets of epimers and created the two required C4 stereocenters from the same chiron, is described. Our strategy may facilitate the development of synthetic design and find more applications in pheromone synthesis.

The reaction between steroidal sapogenins and hydrogen sulfide catalyzed by BF₃·Et₂O is described. The thiodiosgenin and thiotigogenin comprising a sulfur atom on the F ring have been synthesized under this mild reaction conditions.

A formal synthesis of betamethasone from pregnane-3β,16β,20S-triol is described. Key transformations are a bromination-acetylation of triol, an S_N2 reaction of the resulting C16α-bromide with dimethylcopperlithium to get the required C16β-methyl group, and a double hydroxylation to prepare the dihydroxyacetone side chain.

An unusual negative ¹H NMR chemical shift of methyl group in condensation product of isocopalane diterpenoid with p-toluenesulfonyl hydrazide was discovered. 2D NMR, computational studies and single-crystal X-ray diffraction analysis were used to determine the real conformation.

A versatile and divergent two-step transformation of malimides to racemic tetramates and tetramic acids is described. The method consists of Grignard reagent addition with malimides, and concentrated HCl-promoted chemoselective transformations of the latter.

Herein we describe a synthesis of C1–C9 domain 2 of the proposed structure of didemnaketal A, a natural product with important bioactivities, from potassium (2R,4R)-2,5-dihydroxy-4-methylpentanoate 5. Sharpless asymmetric dihydroxylation introduced the chiral vicinal diol and chelation-controlled allylation established another chiral OH.

Described herein is a semisynthesis of azedarachol from pregnanetriol, which featured a symbiotic elimination/deprotection process, an oxidation/reduction procedure for reversing C20 configuration, and a dehydration-dihydroxylation process to introduce 2,3-cis-diol. This synthesis also discloses some interesting selectivities of 16,20-diol unit.

Both enantiomers of 3-methylheptanoic acid have been synthesized from chiral methyl molecules which were derived from (R)-4-methyl-δ-valerolactone (5). A wide variety of chiral 3-methyl alkanoic acids can also be synthesized by the methods described herein.

A seven-step synthetic route was developed to synthesize (+)-subersic acid from (−)-Sclareol. The cross coupling of the diterpene with the arene fragment using the arylation of allylic acetate followed by β-acetoxy elimination type Heck reaction was acted as the key reaction.

Using methyl (R)-5-bromo-4-methylpentanoate, we have accomplished a synthesis of (R)-muscone, a natural macrocyclic musk, based on chiral pool strategy.