Primary allylic selenosulfates (seleno Bunte salts) and selenocyanates transfer the allylic selenide moiety to thiols giving primary allylic selenosulfides, which undergo rearrangement in the presence of PPh3 with the loss of selenium to give allylically rearranged allyl alkyl sulfides. This rearrangement may be conducted with prenyl-type selenosulfides to give isoprenyl alkyl sulfides. Alkyl secondary and tertiary allylic disulfides, formed by sulfide transfer from allylic heteroaryl disulfides to thiols, undergo desulfurative allylic rearrangement on treatment with PPh3 in methanolic acetonitrile at room temperature. With nerolidyl alkyl disulfides this rearrangement provides an electrophile-free method for the introduction of the farnesyl chain onto thiols. Both rearrangements are compatible with the full range of functionality found in the proteinogenic amino acids, and it is demonstrated that the desulfurative rearrangement functions in aqueous media, enabling the derivatization of unprotected peptides. It is also demonstrated that the allylic disulfide rearrangement can be induced in the absence of phosphine at room temperature by treatment with piperidine, or simply by refluxing in methanol. Under these latter conditions the reaction is also applicable to allyl aryl disulfides, providing allylically rearranged allyl aryl sulfides in good yields.

The synthesis of (+/-)-histrionicotoxin has been achieved in just nine steps using a two-directional synthesis strategy. Key reactions include a two-directional cross-metathesis, a tandem oxime formation/Michael addition/1,4-prototopic shift/[3 + 2]-cycloaddition cascade, a selective Z,Z-bisenyne formation, and a one-pot N-O and bischloroacetylene reduction.

3,3,3-Trichloropropyl-1-triphenylphosphonium chloride is conveniently prepared from 2-chloroethanol, triphenylphosphine, and trichloroacetic acid. Deprotonation of this reagent generates 3,3,3-trichloropropyl-1-triphenylphosphorane, which reacts with aldehydes to give trichloromethylated (Z)-olefins, which are useful for the synthesis of (Z)-1,3-enynes, (Z,Z)-1-chloro-1,3-dienes, and 1,3-diynes in high yields and stereospecificities.

Alkyl and aryl allyl disulfides are induced to undergo the desulfurative allylic rearrangement by silver nitrate in protic solvents at room temperature, thereby removing the necessity for the use of phosphines as thiophilic reagents. The silver-mediated reaction functions at ambient temperature in protic solvents and in the absence of protecting groups

Abstract4-Trifluoromethylbenzenepropargyl ethers are stable and sterically minimal alcohol protecting groups that are readily cleaved in a single step by exposure to lithium naphthalenide. In conjunction with the 4,6-O-benzylidene protecting group, glycosylation reactions of 2-O-4-trifluoromethylbenzenepropargyl-protected mannosyl donors are extremely β selective.