Uncatalyzed reactions intermolecular

Oxygen Production by Intermolecular Electron Transfer Processes 61.S.4.S.1 Uncatalyzed reactions... 

Allyl methyl tellurium decomposed in light at 60 to 80° to give tellurium, 1-butene, and 1,5-hexadiene. This uncatalyzed reaction coupled the organic groups both intra- and intermolecularly. ... 

In some cases, direct, uncatalyzed 1,2-addition of diethylzinc to aldehydes becomes a significant problem. Triethylsilane for intramolecular reactions or triethylborane for intermolecular reactions is often helpful to address this issue. 

The secret behind the superb catalytic performance of enzymes is that when an enzyme binds the substrates and cofactors, it turns the uncatalyzed intermolecular readion into an intramolecular reaction [25]. In general, intramolecular reactions are faster than intermolecular ones, because the reading groups are already close to each other. This proximity effect increases the effedive concentration, and with it the rate... 

---