Oxazolines ortholithiation

In 1994, the same authors reported the synthesis of corresponding oxazolines tethered to sulfoxides by ortholithiation of the parent 2-phenyl oxazoline with butyllithium followed by addition of either (5)- or (/ )-/ -tolylmenthyl-sulfinate. Applied as ligands in the test reaetion, these diastereomerie ligands gave very different results, as shown in Seheme 1.25, thus demonstrating the... 

Coordination to strongly orf/zo-directing groups is responsible for the regiochemistry of some other reactions which do not involve ortholithiation. For example, while the electron-withdrawing nature of the oxazoline would be expected to direct the addition of the organolithium nucleophile to benzyne 11 towards the meta position, the major product that arises is the result of addition at the ortho position to give 12 (Scheme 1). ... 

Ortholithiated oxazoline 62 is best transmetallated to its magnesium analogue before reaction with aldehydes. As with the equivalent amide reaction, treatment with 4.5 M HCl then cyclizes the products to lactones (Scheme 31) °. ... 

Oxazolines , imidazolines and tetrazoles can all be laterally lithiated. Oxazolines have been used in this regard rather less than for ortholithiation (Scheme 200). 

---