E1cb Mechanism and Elimination Products

E1cb Mechanism:
The E1cb mechanism is a type of elimination reaction that occurs in a single step. It involves a unimolecular, concerted reaction in which a proton is removed from the β-carbon of a carbonyl group, resulting in the formation of a carbanion intermediate. This intermediate then eliminates the leaving group to form the final product.

Elimination Products:
The elimination products that are formed in the E1cb mechanism depend on the structure of the starting material and the conditions under which the reaction is carried out. In general, there are two types of elimination products that can be formed:

1. Zaitsev Product:
The Zaitsev product is the major product of elimination reactions and is formed via the most stable carbocation intermediate. It is formed when the leaving group is eliminated from the β-carbon that has the most number of alkyl groups attached to it.

2. Hofmann Product:
The Hofmann product is the minor product of elimination reactions and is formed via the least stable carbocation intermediate. It is formed when the leaving group is eliminated from the β-carbon that has the least number of alkyl groups attached to it.

Answer:
In the given reaction, the starting material is a tertiary amine oxide, which can undergo elimination via the E1cb mechanism. Since the amine oxide is tertiary, it can form a stable carbanion intermediate, which will result in the formation of the Zaitsev product as the major product.

Therefore, only one elimination product (including stereoisomers) will be formed in principle, which will be the Zaitsev product. The formation of the Hofmann product is highly unlikely due to the stability of the carbanion intermediate.

In conclusion, only one elimination product (including stereoisomers) will be formed in the given reaction if it proceeds by the E1cb mechanism, which will be the Zaitsev product.