Sulfur and selenium derivatives of 2-phosphaindolizines

✍ Scribed by Raj K. Bansal; Neelima Gupta; Neela Bharatiya; Geetika Gupta; Anushka Surana; Gabriele Hackenbracht; Konstantin Karaghiosoff

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 195 KB
• Volume: 9
• Category: Article
• ISSN: 1042-7163
• DOI: 10.1002/(sici)1098-1071(1998)9:4<445::aid-hc14>3.0.co;2-r

✦ Synopsis

The 2-phosphaindolizines 1 react with hydrogen sulfide and elemental sulfur to give the new zwitterionic heterocyclic systems 2 of the N-pyridiniomethyl dithiophosphinate type. In contrast, no reaction is observed with sulfur alone. MeI methylates 2e,f at sulfur. The analogous pyridiniodiselenophosphinate 5 results from the reaction of 1a with 1,3,2,4diselenadiphosphetane-2,4-diselenide, 4a, in the absence of an additional base. As a further product, the perselenophosphinic anhydride 6 is identified. In the presence of triethylamine, 1a reacts with each of the diselenides 4a-c to give the new triethylammonium diselenophosphinates 7a-c, respectively. This reaction can be extended to 1-aza-2-phosphaindolizine, 8, which yields with each of 4a,b and NEt 3 the diselenophosphinates 9a,b, respectively. The anhydride 6 and the diselenophosphinates 7 and 9 result from an electrophilic substitution at the phosphaindolizine ring.