Another Organocatalysis Example---The Claisen Rearrangement

A particularly active area of study of synthetic chemislry in this century has been in organocatalysis, and as we have discussed earlier, computational chemistry has been a strong parmer in elucidating the mechanism and understanding the stereoinduction. To give a sense of the breadth of activity in this area, the chapter ends with a discussion of a very different reaction, the Claisen rearrangement. 

In a follow-up paper, Jacobsen showed that the chiral guanidinium 80 provides catalytic power and enantioselectivity in the Claisen rearrangement systems such as Reaction 6.36. Here the reaction proceeded in 81 percent yield with an ee of 84 percent. The reaction is also diasteroselective for Reaction 6.37, the diastere-oselectivity increases from 11 1 without catalyst to 16 1 with 80. 

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