Paul G. Gassman

The chemistry of bent bonds : XLIV. Chemical evidence for the structure of the adduct obtained from quadricyclane and di-μ-chlorotetracarbonyldirhodium(I)☆

Abstract The structure of the adduct obtained from the reaction of tetracyclo [3.2.0.0 2,7 0 4,6 ] heptane (quadrdicyclane with di-gm-chlorotetracarbonyldirhodium(I) has been established on the basis of chemical evidence. The structure proposed by Cassar and Halpern was confirmed on the basis of the tricyclic alcohol isolated from the lithium aluminum deuteride reduction of the initially formed rhodium containing adduct.

A Simple Route to Benzofurans

Abstract Recently, we have demonstrated that anilines could be selectively ortho-substituted with relative ease and in high yield via the intramolecular rearrangement of ylids generated from azasulfonium salts.3,4 These azasulfonium salts could be derived from either the reaction of sulfides with N-chloroanilines3 or from the reaction of anilines with chlorosulfonium chlorides.4 Utilizing a variation of this technology we have recently demonstrated that phenols can be selectively ortho-alkylated5 or ortho-formylated.6 These processes are illustrated by the conversion of 1 into 2 in 73% yield and the subsequent reduction of 2 to 3 in 95% yield, and by the transformation of 4 into 6 via 5 in 35% overall yield.

Reductive cleavage of succinic esters. A method for the introduction of acetic acid fragments

Diels–Alder addition of maleic or fumaric esters to 1,3-dienes, followed by catalytic reduction and treatment with sodium in liquid ammonia at –78°, which promotes a solvent dependent reductive cleavage of the carbon–carbon σ bond of the succinic ester fragment, provides a general method for the preparation of derivatives of suberic acid.

Nitrenium ions from hydroxylamine derivatives. A comparison of the transition state for heterolytic cleavage of the N–O versus C–O bond

A ρ-value of + 0·68 has been determined for the methanolysis of a series of piperidin-1-yl benzoates, in comparison with value of ca.+ 1·35 for ρ determined for methanolysis of a series of 1-phenylcyclohexyl benzoates, indicating that the transition state for heterolytic cleavage of an N–O bond to generate a nitrenium ion occurs earlier in the bond breaking process than for heterolytic cleavage of a C–O bond to produce a tertiary carbonium ion.