Negishi cross-coupling of secondary alkylzinc halides with aryl/heteroaryl halides using Pd-PEPPSI-IPent

Electrophilic addition of hydrogen halides, HX (X = Cl, Br or I) to alkenes forms alkyl halides as per Markovnikov's rule, where the hydrogen gets added to the less substituted carbon of the double bond. Hydrohalogenation of alkynes takes place in a similar manner, with the first addition of HX forming a vinyl halide and the second giving a geminal dihalide.

Overview
Alcohols can be synthesized from alkyl halides via nucleophilic substitution reactions. The highly polar carbon-halogen bond in the substrate makes halide a good leaving group. The hydroxide ion or water can act as a nucleophile to take the place of halide and form an alcohol. The substitution reactions occur via two different reaction pathways, SN1 or SN2, depending on the nature of carbon attached to the halide.
Primary alcohols are synthesized from primary alkyl halides, and the...

Introduction
Alkylation of terminal alkynes with primary alkyl halides in the presence of a strong base like sodium amide is one of the common methods for the synthesis of longer carbon-chain alkynes. For example, treatment of 1-propyne with sodium amide followed by reaction with ethyl bromide yields 2-pentyne.

The Wittig reaction is the conversion of carbonyl compounds-aldehydes and ketones-to alkenes using phosphorus ylides, or the Wittig reagent. The reaction was pioneered by Prof. Georg Wittig, for which he was awarded the Nobel Prize in Chemistry.

An SN2 reaction of an alkyl halide is a single-step process in which bond formation between the nucleophile and the substrate and bond breaking between the substrate and the halide occurs simultaneously through a transition state without forming an intermediate.
When the nucleophile approaches the electrophilic carbon with its lone pairs, the halide acts as a leaving group and moves away with the electron-pair bonded to the carbon. Dotted partial bonds represent the bonds being formed or broken...

Organomagnesium halides, commonly known as Grignard reagents, convert acid halides to tertiary alcohols. The reaction requires two equivalents of the Grignard reagent and proceeds via a ketone intermediate.
Grignard reagents are a source of carbanions and function as nucleophiles. The mechanism begins with the nucleophilic attack by the carbanion at the carbonyl carbon of the acid halide to form a tetrahedral intermediate. Next, the carbonyl group is re-formed, and the halide ion departs,...