Question

1) OsO. Pyridine 2) NaHSO, H,0 (show stereochemistry NaOH ethanol OH HIO он HO, THE 74) Synthesize the molecule below starting with acetylene (ethyne). List all reagents used. Show products after each proposed step. (6 points) 75) The following is an E2 reaction. Indicate the product. You MUST also show both chair conformations and indicate the chair conformation in which the elimination occurs. (5 points) NaOEt EIOH Page 9 of 13

Answer 1

0 Osor; pyridine ® Nat503, itzo Answer. TOH Syn-di-ol formation. 1. OH NAOH 6 . 'my. ethanol Has Alpha hydrogen OH Aldol Condensation. » ß-hydroxy Ketone. OHA BOTT H104, OH H2O, THE . 2moles . oxidative cleavage. of vicinal dicols, H NG NH2 H-CEC-H 23 Cesta Br > : B Disia mylborane (W H₂O, nach

Mechanism ① H-c=Q4 + Nå hitz › each | 1-c= + + + (3) V + RBH, M non moren OCH H202,0H tautomerization Br NaoFL Br [Note: for E2, the leaving group Br must be anti- periplaner to 'H' to be . eliminated] .. E2 reaction is shown below ELOH The w ELO Base I Tproduct a - Answer Note, she chain conformation in which "Br" is axial (as shown above) is suitable for Ez. . > This conformer has Br at euitorial position - Hence not By Suitable.