Building on the classical theory of process algebra with priorities, we identify a new scheduling mechanism, called "sequentially constructive reduction" which is designed to capture the essence of synchronous programming. The distinctive property of this evaluation strategy is to achieve determinism-by-construction for multi-cast concurrent communication. In particular, it permits us to model shared memory multi-threading with reaction to absence as it lies at the core of the programming language Esterel. In the technical setting of Milner's CCS extended by clocks and priorities, we prove for a large class of processes, which we call "structurally coherent" the confluence property for constructive reductions. We further show that under some syntactic restrictions, called "pivotable" the operators of prefix, summation, parallel composition, restriction and hiding preserve structural coherence. This covers a strictly larger class of processes compared to those that are confluent in Milner's classical theory of CCS without priorities.