Question

1. Predict the major product of the reaction. Clearly indicate stereochemistry, if necessary (3 pts) Ph H2 Lindlar cat Me hexanes 2. Provide reagents to achieve the shown multi-step transformations (6 pts) an MO

Answer 1

1 6 me Me =ph + Lindlar Catalyst Ph. is difin. Lindlar catalyst reduced alkyne to cis alkene selectively whereas Lillig NH3 gives trans alkene. Br 2) Ph a Br2 (excess) Br/ NONH2 ceso Ph - 2H Br Ph - H INONH Ph 112 Me Bor -Bv 1) NANH2 ii) Me-c=cn Br Lindlar Me Ph = Ph. e=c-me catalyst The first step bromination using exuss Brz followed by 2 equivalent HBr elimination to give phenylacetylene, Then further alkylation followed by selective reduction to cis alkene of both alkyne.