In what cases are synchronous architectures more appropriate than asynchronous architectures

Synchronous architectures are more appropriate than

asynchronous architectures in applications where the sender

and receiver must participate in a message exchange, and the

sender must respond to the receiver in a limited time frame.

An example of this is credit card authorization. The sender

needs a response within a short time to complete a

electronic commerce transaction and to notify a user that

his purchase has been completed.