REACTION OF CHLOROSULFONYL ISOCYANATE WITH BRIDGED BI- AND TRICYCLIC OLEFINS

The addition of chlorosulfonyl isocyanate (CSI) to norbornene (5), norbornadiene (24), 7-benzoyloxy- (28) and 7-t-butoxynorbornadiene (30), endo- (32) and exo-dicyclopentadiene (37), and bicyclo[2.2.2]oetene (40) led, in each case, to a single, unrearranged cycloadduct, the N-chlorosulfonyl-β-lactam. A nonconcerted cycloaddition mechanism is proposed. Attempts to form the bis adduct from norbornadiene were unsuccessful. Assignment of the exo configuration to the azetidinone ring in these N-chlorosulfonyl-β-lactams is based predominantly on nmr evidence. Benzenethiol-pyridine reduction of the N-chlorosulfonyl cycloadducts led to the corresponding unsubstituted β-lactams. The infrared spectrum of exo-2-p-toluenesulfonamido-3-carboxybicyclo[2.2.1] heptane (14), ultimately prepared from the norbornene cycloadduct, expectedly differed from that of the endo isomer (18) prepared by a stereospecific Lossen rearrangement on N-phenylsulfonyloxynorbornane-endo-2,3-dicarboximide (16). Treatment of N-phenylsulfonyloxynorbornane-exo-2,3-dicarboximide (21) under Lossen conditions failed to yield rearrangement product, as did the Hofmann reaction on norbornane-exo-2,3-dicarboximide (22) and exo-2-carbomethoxy-3-carboxamidonorbornane (23). A Lossen rearrangement, however, successfully converted N-sulfonyloxybicyclo[2.2.2]octane-2,3-dicarboximide (46) into 2-amino-3-carboxybicyclo[2.2.2]octane hydrochloride (43), identical with the acid hydrolysis product of the β-lactam cycloadduct from 40. © 1968, American Chemical Society. All rights reserved.