New Synthesis of Benzothiazines and Benzoisothiazoles Containing a Sulfoximine Functional Group

Abstract

The reaction of S-2-bromophenyl-S-methylsulfoximine with terminal alkynes in the presence of a palladium catalyst resulted in the formation of both 1,2-benzothiazines and 1,2-benzoisothiazoles. A preference for the former was seen with alkylalkynes, while the latter were preferentially formed with alkynylarenes.

Transition metals in organic synthesis: Highlights for the year 2005

“…A related nickel-catalyzed reaction was reported [487]. Palladium catalyzed the formation of benzothiazines and benzoisothiazoles from S-2-bromophenyl-S-methylsulfoxime and terminal alkynes [488]. Palladium catalyzed the reaction of 3-haloimidazo[1,2-a]pyridine-2-carbaldehyde imine with alkynes to give dipyrido[1,2-a;3 ,4 -d]imidazoles (Eq.…”

Formation of a benzothiazine via the reaction of ortho-halo sulfoximines with copper salts

“…9 We have speculated that metallocycles might arise from the Scheme 1. Proposed formation of the cyclic bis-sulfoximine 3.…”

“…To that end, we decided not only to investigate the chemistry of 1a, 9 but also of the chlorine and iodine analogues 1b 12 and 1c. The synthesis of all 3 congeners is shown in Scheme 2 and followed a standard protocol for the synthesis of sulfoximines of this general type.…”

Rhodium(III)‐Catalyzed C−H Alkynylation of N‐Methylsulfoximines

“…Along with the rapid expansion of transition‐metal‐catalyzed C−H activation in recent decades, direct C−H alkynylation reactions have recently been developed as a desirable method for facile synthesis of alkyne derivatives from C(sp 2 )−H and C(sp 3 )−H bonds . But till now, the only known method to make ortho ‐alkynylated sulfoximines is still normal Sonogashira‐type cross‐coupling from ortho ‐bromo or ‐iodo sulfoximines (Scheme a), where the requirement of preinstalling halogen atoms onto the arenes definitely caused some problems on atom‐ and step‐economy for the synthesis of target sulfoximines. Herein, we reported a rhodium(III)‐catalyzed direct alkynylation of ortho ‐C−H bonds on aryl sulfoximines, in which both diaryl and ( S , S )‐alkyl aryl sulfoximines are well compatible with this transformation (Scheme b).…”