does not occur like that. The two substrates first react in a condensation reaction (I believe- it's in one of the many papers I've posted in the digest on Ephedrine under the AKABORI section- HINT, HINT, HINT....)
Once the two have united, then the mix is heated to the point of decarboxylation of the product formed in the previous step.
Yes, see thats what I was talking about. And yes, the AKABORI thing I've read before, where they talked about using serine and shit. Interesting stuff!
Patent DE389881 (http://l2.espacenet.com/dips/viewer?PN=DE389881&CY=gb&LG=en&DB=EPD)