Generation of Sulfur-Functionalized Nitrile Oxide, (Phenylthio)acetonitrile Oxide, and Synthetic Applications

Abstract

The first generation of a new sulfur-functionalized nitrile oxide 1,3-dipole, (phenylthio)acetonitrile oxide, is presented. Its cycloadditions to a variety of olefins and acetylenes lead to 3-(phenylthiomethyl)-2-isoxazolines and -oxazoles, the formers being selectively deprotonated at the carbon substituted by the sulfur moiety. The resulting sulfur-stabilized carbanions react with aldehydes, esteric Michael acceptors, and alkyl halides to enable the introduction of a carbon substituent to the side chain on 3-position. Raney Ni reduction of these 2-isoxazolines gives β,β′-dihydroxy ketones and β-hydroxy ketones.

Synthesis of the Aziridinomitosene Skeleton by Intramolecular Michael Addition: α-Lithioaziridines and Nonaromatic Substrates

“…The main difference in this route compared to the precedent was in the use of a potentially removable nitrogen substituent, the N -benzenesulfonylethyl group. Thus, the known oxime 18 was reduced with NaCNBH 3 to afford hydroxylamine 19 and condensation of the crude 19 with 1,3-cyclohexanedione ( 20 ) afforded the vinylogous hydroxamic acid 21 . Treatment of 21 with ethyl propiolate and i -Pr 2 NEt at room temperature then produced aminal 24 via Michael addition of 21 , oxaza-Claisen rearrangement of 22 , and ring closure of the aldehyde intermediate 23 .…”

Facile Synthesis of 3-Thiomethyl-2-isozoline Derivatives: New Sulfide Formation from Epoxide Containing Isoxazolines via Retro-Aldol Type Reaction

“…Enatiomerically pure 3-sulfinylmethyl-2-isoxazolines prepared from the exo-metallation of 3-methyl-2-isoxazolines followed by the reaction of (-)-(S)-menthyl toluene-p-sulfinate [2] were good synthons for a variety of chiral b-hydroxy ketones and g-amino alcohols. 3-Phenylthiomethyl-2-isoxazolines were first prepared from phenylthioacetonitrile oxide with olefins in 1988, [7] and they derived various b-hydroxy ketones from the resulting isoxazolines. Synthetic procedures of sulfinylmethyl and phenylthiomethyl derivatives were not only simple but also the yields were not considerably good.…”