Table 2.
Examination of Acid and Base additives in the Allene Hydrocarbonation Reaction
 | |||||
|---|---|---|---|---|---|
| entry | acid (mol%) | base (mol%) | % yielda | d.rb | % eec |
| 1 | none | none | 91 | 2.6:1 | 34 |
| 2 | PhCO2H (10) | NEt3 (10) | 92 | 6.4:1 | 80 |
| 3 | PhCO2H (20) | NEt3 (10) | 92 | 6.1:1 | 83 |
| 4 | PhCO2H (10) | NEt3 (20) | 96 | 5.7:1 | 80 |
| 5 | PhCO2H (10) | KOtBu (5) | 87 (>99) | 5.6:1 | 74 |
| 6 | hippuric acid (10) | KOtBu (5) | 88 (97) | 4.9:1 | 74 |
| 7 | hippuric acid (20) | KOtBu (5) | 78 (98) | 4.5:1 | 75 |
a
Determined by 1H NMR with respect to mesitylene as the internal standard, number in parantheses refers to yield based on unreacted 10.
b
Determined by 1H NMR of the unpurified reaction mixture.
c
Determined by chiral HPLC analysis.