[header] How to be familiar with various types of mechanisms of organic reactions [title] Organic reactions can usually proceed in one of two ways. [step] One of them is concerted reaction that takes place in one step with one transition state. The other type of reactions in organic chemistry is the non-concerted type of reactions. 
The latter type is the dominant type of most chemical reactions. Non-concerted organic reactions usually have intermediate structures that are highly reactive carbon species.