Search results
Results from the WOW.Com Content Network
The designations 1,2 and 1,4 are derived from numbering the atoms of the starting compound where the oxygen is labeled “1” and each atom adjacent to the oxygen are sequentially numbered out to the site of nucleophilic addition. A 1,2-addition occurs with nucleophilic addition to position 2 while a 1,4-addition occurs with nucleophilic ...
This reaction produced the 1,6-addition product 2 in 0% yield, the 1,6-addition product 3 in approximately 99% yield, and the 1,4-addition product 4 in less than 2% yield. This particular catalyst and set of reaction conditions led to the mostly regioselective and enantioselective 1,6-Michael addition of ethyl sorbate 1 to product 3 .
Cyclohexene derivatives, such as imines, epoxides, and halonium ions, react with nucleophiles in a stereoselective fashion, affording trans-diaxial addition products. The term “Trans-diaxial addition” describes the mechanism of the addition, however the products are likely to equilibrate by ring flip to the lower energy conformer, placing the new substituents in the equatorial position.
Safety-critical applications use redundant double-ring configurations. In a MOST network, one device is designated the timing master. Its role is to continuously supply the ring with MOST frames. A preamble is sent at the beginning of the frame transfer. The other devices, known as timing followers, [1] use the preamble for synchronization.
Note that if a Grignard reagent (such as RMgBr) is used, the reaction with an enone would instead proceed through a 1,2-addition. The 1,4-addition mechanism of cuprates to enones goes through the nucleophilic addition of the Cu(I) species at the beta-carbon of the alkene to form a Cu(III) intermediate, followed by reductive elimination of Cu(I ...
It is common practice in diagrams to draw a line under the lead end to assist in understanding the method. Most methods have a plain course consisting of a number of leads where the pattern is the same, but different bells are in differing places. In the diagram given, the number 4 bell rings the same pattern as the number 2, but one lead earlier.
In this notation, a Diels-Alder reaction is a (4+2)cycloaddition and a 1,3-dipolar addition such as the first step in ozonolysis is a (3+2)cycloaddition. The IUPAC preferred notation however, with [i+j+...] takes electrons into account and not atoms. In this notation, the DA reaction and the dipolar reaction both become a [4+2]cycloaddition.
Explicitly, the pushout of the morphisms f and g consists of an object P and two morphisms i 1 : X → P and i 2 : Y → P such that the diagram commutes and such that (P, i 1, i 2) is universal with respect to this diagram. That is, for any other such triple (Q, j 1, j 2) for which the following diagram commutes, there must exist a unique u ...