Question

A. Explain why tosylates make good leaving groups. B. What is the orientation of the stereogenic center after the reaction depicted in the figure? н 1. Cl-Ts, pyridine он (R) 2. SCH3, THF

Answer 1

The structure of Tosylate- Ou=0 - <H3S 8 the tosylate Let us consider a reaction in cutich group act as a leaving group. a (It is a nucleophile) K-TG- S H Rasph - (13 (cleavage OFR-o' (product) + (Alkyl to sylate) bond ) Any alkyl group or like -CH₂-Et, - CH₂ CH₂ CH₃ eta] o Leaving ghoud curry in the above reaction the 2-03 bond cleaved by Nucleophile and to sylate group act as a leaving a boup » que know the Highero the ressonating stroucture here of the anion highelm will be the stability of the anion. The besonating structune of the To sylate group - A CH₂ 777 As we see the three beosonating structune the negative change decolised on the more electronegative oxygen atom.

and the three ressonating structures are equivalent so due know the equivalent besso nating strouctunes contribute more 18 bessonce energy sos this (tosylate) is very stable so, Due to gaining of stability to sylate group act as a leaving group and cleavage of R-0' bond occurs.