Predicting the Products

We mentioned that predicting the products of substitution and elimination reactions requires three discrete steps  

The nucleophile attacks the a position, where the leaving group is connected. 

The nucleophile replaces the leaving group with inversion of configuration. 

The nucleophile attacks the carbocation, which is generally where the leaving group was originally connected, unless a carbocation rearrangement took place. 

---

The EROS (Elaboration of Reactions for Organic Synthesis) system [26] is a knowledge-based system which was created for the simulation of organic reactions. Given a certain set of starting materials, EROS investigates the potential reaction pathways. It produces sequences of simultaneous and consecutive reactions and attempts to predict the products that will be obtained in those reactions. 

It may be desirable to predict which crystal structure is most stable in order to predict the products formed under thermodynamic conditions. This is a very difficult task. As of yet, no completely automated way to try all possible crystal structures formed from a particular collection of elements (analogous to a molecular conformation search) has been devised. Even if such an effort were attempted, the amount of computer power necessary would be enormous. Such studies usually test a collection of likely structures, which is by no means infal-... 

This method is a little labor-intensive because it involves a lot of distilling, but it is so easy to do and the results are absolutely predictable The production of MD-P2P or P2P using this method has been previously described [8,9] except that Strike is going to describe the little things. You know, those little bullshit things that never seem to work their way into official accounts but always cause a lot of stress to the novice chemist. 

Each of the following nucleophilic substitution reactions has been reported in the chemical literature Many of them involve reactants that are somewhat more complex than those we have dealt with to this point Nevertheless you should be able to predict the product by analogy to what you know about nucleophilic substitution in simple systems... 

Each of the following reactions has been reported in the chemical literature Predict the product in each case showing stereochemistry where appropriate... 

Predict the product of the reaction of propanal with each of the following... 

Predict the products formed when each of the following isotopically substituted denvatives of chlorobenzene is treated with sodium amide in liquid ammonia Estimate as quantitatively as possible the composition of the product mixture The astensk ( ) in part (a) designates C and D in part (b) is... 

Mechanism. The thermal cracking of hydrocarbons proceeds via a free-radical mechanism (20). Siace that discovery, many reaction schemes have been proposed for various hydrocarbon feeds (21—24). Siace radicals are neutral species with a short life, their concentrations under reaction conditions are extremely small. Therefore, the iategration of continuity equations involving radical and molecular species requires special iategration algorithms (25). An approximate method known as pseudo steady-state approximation has been used ia chemical kinetics for many years (26,27). The errors associated with various approximations ia predicting the product distribution have been given (28). 

Many researchers have correlated the overall decomposition as an nxh. order reaction, with most paraffins following the first order and most olefins following a higher order. In general, isoparaffin rate constants are lower than normal paraffin rate constants. The rate constants are somewhat dependent on conversion due to inhibition effects that is, the rate constant often decreases with increasing conversion, and the order of conversion is not affected. This has been explained by considering the formation of aHyl radicals (38). To predict the product distribution, yields are often correlated as a function of conversion or other severity parameters (39). 

Predict the products formed on oxidation of each of the following with periodic acid ... 

Use Markovnikov s rule to predict the products of HBr addition to the alkenes shown above. 

Predict the products of electrophilic nitration of toluene, aniline and nitrobenzene. 

Obtain the energy of each cation that might be generated by electrophilic addition of Br to biphenyl (biphenyl+Br+). Which one is most stable Are there others of comparable stability Examine the structure of the most stable cation(s), and draw all of the resonance contributors needed to describe this ion(s). Predict the product(s) of biphenyl bromination. Will the reaction be highly selective, moderately selective or unselective ... 

Problem 5.9 Predict the products of the following polar reaction, a step in the citric acid cycle for food metabolism, by interpreting the flow of elections indicated by Uie curved arrows ... 

Strategy When predicting the product of a reaction, you have to recall what you know about the kind of reaction being carried out and then apply that knowledge to the specific case you re dealing with. In the present instance, recall that the two methods of... 

Name the following alkenes( and predict the products of their reaction with (i) Twta-chloroperoxybenzoic acid, (ii) KMn04 in aqueous acid, and (iii) O3, followed by Zn in acetic acid ... 

Predict the products of the following reactions (the aromatic ring is unreac-tive in all cases). Indicate regiochemistry when relevant. 

Predict the products from reaction of 1-hexyne with the following reagents (a) 1 equiv HBr (b) 1 equiv Cl2... 

Interactive to predict the products and stereochemistry of alkene addition reactions. 

Tell whether each of the following reactions is likely to be SN 1, S 2, El, ElcB, or E2, and predict the product of each ... 

Predict the product and give the stereochemistry resulting from reaction of each of the following nucleophiles with CR)-2-bromooctane ... 

Predict the product(s) of the following reaction, indicating stereochemistry where necessary ... 

Predicting the Product of sn Electrophilic Addition Reaction of a Conjugated Diene... 

Predict the product of the following Diels-Alder reaction ... 

---