ChemInform Abstract: Diastereoselective Synthesis of α,γ‐Amino Alcohols by Intramolecular 1,3‐Dipolar Cycloaddition of Nitrones with Allyl Thioether Moieties and Subsequent Reductive Ring Cleavage.

Abstract

The allylthio nitrones (IV) and (VIII), derived from mercaptoacetaldehyde (I) and allyl bromide (II) or from acrolein (VI) and allyl mercaptan (VII), undergo intramolecular cycloaddition, forming the fused isoxazolidines (V) or (X) and the bridged oxathiazine derivatives (IX).

Bidirectional Synthesis of the IJK Fragment of Ciguatoxin CTX3C by Sequential Double Ring-Closing Metathesis and Tsuji–Trost Allylation

“…Cleavage of both silyl ethers was accomplished by treatment of the diene 7 with tetra- n -butylammonium fluoride. The resulting diol 8 was then subjected to double alkylation with α-chloroketophosphorane 9 . , The resulting bis -ylide 10 was then reacted with formaldehyde, butanal, or 2-(2-propen-1-ylthio)­acetaldehyde to give the RCM substrates 11a – c with variable yields. Subsequent reduction of the bis -enone 11b under Luche conditions delivered the diol 12 , the fourth RCM substrate required for exploration of the bidirectional strategy, as a complex mixture comprising all four diastereomers.…”