Stereoselective Synthesis of Dienes from N-Allylhydrazones

Abstract

A new method for the stereoselective synthesis of dienes from aldehydes and N-allylhydrazine derivatives has been developed. High levels of (E)-stereoselectivity are obtained for a variety of substrates. Addition of a dienophile to the reaction mixture allows a one-flask diene synthesis-cycloaddition sequence.

Traceless bond construction via rearrangement of N-Boc-N-allylhydrazones giving 1,1-disubstituted olefins

“…For a better comparison we focused on aldehydes, which had been employed in the foregoing investigations of the Thomson group. 4,13,14 …”

Single‐Electron/Pericyclic Cascade for the Synthesis of Dienes

“…Numerous other synthetic methodologies have also utilized diazene intermediates, including vinyl diazenes in the Shapiro reaction, [4] allyl diazenes in Hutchins [5] and Kabalka [6] reactions, and alkyl silylated diazenes from Myers et al [7] Hydrazones have also been used to access diazoalkanes in Bamford-Stevens reactions [8] and allylated diazoalkanes in recent examples by Thomson and co-workers. [9] One transformation that is notably absent from the literature is the conversion of hydrazones into cyclic diazenes, [10] which readily undergo cycloreversions to access dienes in high diastereoselectivities. [11] Currently, there is only one method for the synthesis of dienes from hydrazones, and it is limited to aryl hydrazones.…”

“…[11] Currently, there is only one method for the synthesis of dienes from hydrazones, and it is limited to aryl hydrazones. [9] A new and direct method for the conversion of hydrazines into dienes would not only represent the first example of accessing cyclic diazenes from hydrazones, but it also may provide a solution for the unsolved challenge of directly forming dienes from alkyl hydrazones.…”

Nickel‐Catalyzed Allylic Substitution of Simple Alkenes

“…The complete results are summarized in the Supporting Information. [43] (E)-Buta-1,3-dienylbenzene (3 e) was previously reported. A test tube (borosilicate glass, 16 100 mm) and a stirrer bar were ovendried and brought into a glovebox.…”