Halogenovinyl Sulfones. 6.¹ Synthesis of Condensed Heterocycles by Diastereoselective Intramolecular Diels−Alder Reactions of Sulfonyl-Substituted Trienes

Abstract

Sulfonyl trienes having a chiral center on the allyl carbon of the diene moiety were prepared from L-amino acid as chiral building blocks. Intramolecular Diels-Alder reaction of the sulfonyl trienes having E-geometry on the diene moiety proceeded on the si-face and exo-selectively to give cis-isoindoles as a sole product in good yields. But using the sulfonyl trienes having Z-geometry on the diene part, the ratio of the diastereomers of the products decreased to about 80:20. The observed stereoselectivity can be explained by calculations with semiempirical and ab initio methods.

Palladium‐Catalyzed Aminomethylation of Nitrodienes and Dienones via Double C—N Bond Activation

“…The dienyl allylic amines and their derivatives are not only important building blocks for the synthesis of various nitrogen‐ containing compounds, but also widely found in natural products as well as biologically active molecules. [ 1‐6 ] It is a surprise to find that the catalytic reactions for constructing such a kind of scaffolds remain largely undeveloped, and only few Ir‐catalyzed allylic aminations of dienyl allylic carbonates or alcohols have been reported. [ 7‐8 ] On the other hand, the reaction of activated functionalized dienes with imines or iminium salts under the Morita‐Baylis‐ Hillman (MBH) conditions is another promising approach to functionalized dienyl allylic amines.…”

Vinylphosphonium and 2-aminovinylphosphonium salts – preparation and applications in organic synthesis

“…Vinylphosphonium salts can also be directly converted into the corresponding ylides by potassium tert -butoxide and subjected to the Wittig reaction as described by Yamamoto et al ( Scheme 25 ). The transformation resulted in polyenes 35 of Z- configuration in a relatively low yield of 10–36% [ 41 ].…”

Stereo-, Regio-, and Chemoselective [3 + 2]-Cycloaddition of (2E,4E)-Ethyl 5-(Phenylsulfonyl)penta-2,4-dienoate with Various Azomethine Ylides, Nitrones, and Nitrile Oxides: Synthesis of Pyrrolidine, Isoxazolidine, and Isoxazoline Derivatives and a Computational Study

“…Initially, N -(methoxymethyl)- N -((trimethylsilyl)­methyl)­benzylamine ( 24c ) was selected as the dipole for the bis­[3 + 2]-cycloaddition of diene 1a as outlined in Scheme . All of the azomethine precursors 24a – c were prepared by the known literature procedure and were characterized thoroughly by spectral means. When 1a reacted with 24a – c in the absence of microwave irradiation, it led to a mixture of mono- and bisadduct only even under prolonged heating conditions (24 h) in various solvents.…”