Additions to Bicyclic Olefins. p-Thiocresol and Norbornylene

Reactive intermediates in the bicyclo[3.1.0]hexyl and bicyclo[3.1.0]hexylidene systems. VI. Free-radical addition of methanethiol and methanethiol-d to bicyclo[3.1.0]hex-2-ene

“…Neither bridged thiyl radical 13 nor trans-substituted 2 can be the sole product determining intermediate leading to 5, since the reaction is not completely stereospecific, and the necessity for involving either intermediate as part of an equilibrium with classical radicals 12 and 9 is reduced by the possibility that steric access to the concave side of bicyclo[3.l.Ojhexane may be greater than to the endo side of norbornane. We see some evidence of this in this work in the ratios of thio ethers 6, 4, and 5 formed in the addition of methanethiol to 1, while, in contrast, in analogous radical additions of p-thiocresol (no endo attack observed) 18 and thiophenol (99.5% exo attack)16 to norbornene, steric control appears to be more severe. 19 Similarly, electrophilic addition of DC1 to bicyclo [3.1.0]hexene-2 proceeds by a route involving cis addition of the elements of DC1 to the double bond, but with attack at both the trans and cis faces of the double bond in a ratio of 66:31,4a while similar additions of DC1 to nor- ceed via cis-exo stereochemistry for that portion of reaction leading to unrearranged product.…”

Bridged Polycyclic Compounds. XXI. The Ionic Chlorination of 9, 10-Dihydro-9, 10-ethenoanthracene1

“…Free-radical reactions in bridged bicyclic systems of this type have not led to rearrangement, although evidence for such rearrangements has been sought. [20][21][22] The simplest mechanism which might be proposed involves addition of a chlorine cation to I to yield the classical carbonium ion XV which then rearranges to the more stable benzylic cation XVI. Coordination of XVI with chloride ion would give products II and III.…”

Stereochemistry of Free Radical Additions to Olefins.

“…In 1954 Cristol and Brindell (17) reported the exclusive formation of the exo isomer in the addition of p-thiocresol to norbornene. These results show once again the striking sterie blocking of the ethano bridge.…”