Question

(a) Pericyclic Reactions Predict the major product of each of the following Diels-Alder cycloadditions. Your answer should include an explanation of the regio- and stereoselective outcome of each reaction. NHCH Ph (b) Use the frontier molecular orbital approach to predict the stereochemical outcome of the following 4x electrocyclic, ring-closing reactions. (c) Give a mechanism for each step in the following reaction, showing the key conformer which accounts for the observed stereochemistry of the product. 1. Me (OE) Qara Qar (d) Give the mechanism and product for the following reaction. PV Seo

Answer 1

Answer-a UNHCH₂ Ph NHCH₂ Ph NHCH, P. с Но 11 сна осно ул. W са сно major соо Н . снэ TullcooH

Answer-b Mechanism; - In, he pathway, the HOMO of the substrate is Y ie. Ha Mechanism. – In heating pathway the Home of the substrate is Yie.

Answer-e 1. Mec (OEZ), H+ 2.4 Mechanismi- OEL OEL (+) OL OEE OEL H OEL OEL H-shift ELOH (A) OH Et Et Et Et PH

Answer-d seo2 ph Ph Mechanism: HO50-03 + Se си, CH₂ SHO: Hose H2O CH₂ OH