A3-1 ,3,4-thiadiazolines (111) in this respect. Pyrolysis of these compounds furnished episulphides, which in turn gave the desired olefins upon treatment with

The preparation and reactions of di-t-butyl selenoketone (Ib) and of (-)-selenofenchone (IIb) are described ; fenchylidenefenchane (VI) has been synthesised.

Esters are formed from carboxylic acids and alkyl iodides upon treatment with t-butyl hypochlorite and iodine in carbon tetrachloride. Evidence is presented for a heterolytic mechanism whereby the iodine in the alkyl halide is replaced by the acyloxy-group of the acyl hypoiodite in the presence of iodine monochloride.

Treatment of disulphides, especially diphenyl disulphide. with chloramine-T affords a series of reagents which react with olefins to give adducts. These reactions are electrophilic in nature, with PhS+ initiating the reaction and a complex nitrogen anion terminating the process. Similar, but less extensive, experimentation has been carried out with diselenides, especially diphenyl diselenide. These new reagents provide a novel procedure for the amination of the ethylenic linkage.SELENO-AND SULPHO-DI-IMIDES have recently been utilized to effect allylic amination of olefins l-3 and 1,2diamination of 1,3-diene~,~ and chloramine-?. (N-chloro-N-sodio-4-methylbenzenesulphonamide) in the presence of osmium tetraoxide has been shown to cause stereospecific cis vicinal oxyamination of 01efins.~ We now report a simple method of 1,2-trans-thio-and selenoamination of olefins based on the ' oxidative imination ' of disulphides and diselenides with chloramine-T. These new methods are, in principle, applicable to partial syntheses of aminoglycoside antibiotics.Diphenyl disulphide (1) reacted with anhydrous chloramine--r (5) in acetone to give a crystalline product (PhSSPh)(NTs), [(6), ( 7 ) , or (S)], m.p. 125-130" (decamp.) (Scheme l ) , analogous to the product [( 9), (lo), or t Part 8, D.

Treatment of disulphides, especially diphenyl disulphide, with chloramine-T affords a series of reagents which react with olefins to give adducts. These reactions are electrophilic in nature, with PhS+ initiating the reaction and a complex nitrogen anion terminating the process. Similar, but less extensive, experimentation has been carried out with diselenides, especially diphenyl diselenide. These new reagents provide a novel procedure for the amination of the ethylenic linkage.SELENO-AND SULPHO-DI-IMIDES have recently been utilized to effect allylic amination of olefins and 1,2diamination of 1,3-diene~,~ and chloramine-?. (N-chloro-N-sodio-4-methylbenzenesulphonamide) in the presence of osmium tetraoxide has been shown to cause stereospecific cis vicinal oxyamination of 01efins.~ We now report a simple method of 1,2-trans-thio-and selenoamination of olefins based on the ' oxidative imination of disulphides and diselenides with chloramine-T. These new methods are, in principle, applicable to partial syntheses of aminogl ycoside an ti bio tics.Diphenyl disulphide (1) reacted with anhydrous chloramine-T (5) in acetone to give a crystalline product (PhSSPh)(NTs), [(S), (7), or (S)], m.p. 125-130" (decamp.) (Scheme l ) , analogous to the product [(S), (lo), or