REACTION OF CHLOROSULFONYL ISOCYANATE WITH ALLENES AND OLEFINS

The addition of chlorosulfonyl isocyanate to alienes (2,4-dimethyl-2,3-pentadiene, 2-methyl-2,3-pentadiene, 2,3-pentadiene, 3-methyl-1,2-butadiene, pentamethyleneallene, 1,3-diphenylpropadiene, phenylpropadiene, and cyclononadiene) has been studied. In all cases, initial electrophilic attack occurred at the central carbon atom of the allenic system to produce, in the transition state, an allyl-type stabilized carbonium ion. Structures of the N-chlorosulfonyl-β-lactam cycloadducts and/or 2-carboxamido-1,3-butadiene products have been established on the basis of nmr spectroscopy and conversion into authentic derivatives prepared independently by the reaction of chlorosulfonyl isocyanate with the appropriate olefin. In the case of 3-methyl-1,2-butadiene, a third product identified by degradation and synthesis as 1-chlorosulfonyl-1-(2-carboxy-3-methyl-2-butenyl)urea was obtained. Chlorosulfonyl isocyanate added stereospecifically to cis- and trons-β-methylstyrene to lead to the cisand traros-β-Iactam, respectively, hydrolysis of which led to erythro- and ifireo-3-amino-2-methyl-3-phenylpropanoic acid hydrochloride. This experimentally determined relationship permitted assignment of the geometry of a number of β-lactam, carboxamido-1,3-butadiene, and amino acid products. © 1968, American Chemical Society. All rights reserved.