Organic Chemistry: CHEM 231B
Spring 2002 - Whittier College
Problem Set #1
September 8, 2003
1. Predict the 1H and 13C NMR spectra and the main functional group peaks from the IR spectrum
for the following compounds:
1a.
OCH3
1b.
O
O
O
H
2. Bob wanted to convert [4S, 5S] 5-hydroxy-4-methylheptan-2-one (Compound A) into [4S, 5S] 5-
methyoxy-4-methylheptan-2-one. Therefore, he took Compound A and reacted it with tosyl chloride
and pyridine, worked up the reaction, isolated the product and then added 1 eq of NaOCH3. Upon work
up, he isolated a compound (B) with the following spectral data:
1H NMR:
0.91 triplet int 3 2.21 quintet int 2
1.61 doublet (2Hz) int 3 3.05 singlet int 2
2.13 singlet int 3 5.40 complex multiplet int 1
IR:
3050 medium 2965 strong 1732 strong 1656 medium
1406 weak various peaks in the fingerprint region
2a. Did Bob get his desired product? Explain thoroughly.
2b. If not, what product (B) did he get?
2c. Bob washed his product (B) with acid and reanalyzed his product and discovered that he now
had a different product with the following NMR:
0.87 triplet (6 hz) int 3 1.15 sextet (6 hz) int 2
1.95 doublet of triplets (6 & 2 Hz) int 2 2.06 doublet (2 hz) int 3
2.12 singlet int 3 5.97 sextet (2 hz) int 1
2c.cont What is the product of this reaction?
2d. Write a mechanism that accounts for the formation of this product.
