Looking for articles and or theories that explore the idea that morphology and syntax are not separate but operate on the same principles; for example, that the sentence is just an extended morphological word (using those terms generally, external of their various theoretical use).
First, I'll point to a previous question on this SE, What meaningful distinction is there between morphology and syntax?. I'll just present one line of approach.
A seminal article is Mark Baker's 1985 The Mirror Principle and morphosyntactic explanation, wherein he defines the Mirror Principle as follows:
Morphological derivations must directly reflect syntactic derivations (and vice versa).
Subsequently, Distributed Morphology (DM) was developed by Morris Halle & Alec Marantz and colleagues. I quote from their 1993 paper, Distributed Morphology and the pieces of inflection (pdf):
[...] we take the phonological realization of the terminal elements in the syntax to be governed by lexical (Vocabulary) entries that relate bundles of morphosyntactic features to bundles of phonological features.
We have called our approach Distributed Morphology to highlight the fact that the machinery of what traditionally has been called morphology is not concentrated in a single component of the grammar, but rather is distributed among several different components.
Two points: first, it is in a sense the opposite of what you mention in your question, in that a morphologically derived word is claimed to have internal syntactic structure. Second, DM is not pure syntax (hence the "Distributed" label): it does have a number of post-syntactic operations that derives morphological generalizations such as syncretism (where different morphosyntactic feature bundles like first person singular and second person singular are realized by the same morpheme).
There are a number of resources for DM:
Heidi Harley and Rolf Noyer 1999, State-of-the-Article: Distributed Morphology (pdf), another overview which also has an attached bibliography
David Embick and Rolf Noyer 2006, Distributed Morphology and the syntax-morphology interface (pdf), a handbook article
Andrew Nevins and Karlos Arregi 2012, Morphotactics: Basque Auxiliaries and The Structure of Spellout, a recent book that shows Distributed Morphology "in action" by using the framework to account for the morphosyntax of the Basque auxiliary system.
If one focuses on morphosyntax (inflectional morphology), the differences might be hard to spot. On the other hand, morphological creation of new words (derivational morphology) seems to rely on some different principles. For example:
- Idioms are essential to derivational morphology. Existing words change meaning during their existence. The existence of words is so fundamental people argue about it all the time. Sentences usually don't have existence, no one complains about people making up new sentences.
- New coinage don't have to be transparent. They can be interpreted through their components and through the context. The sum of information as to reach a certain level to achieve comprehension.
Human language users commit some things about their language to memory, but for other matters, they wing it. The memorized things must be finite in number, of course, because we have only a finite amount of time to memorize and a finite capacity to store memories. But the rest of the language, which we create and understand ad hoc, from expression to expression, is infinite.
We memorize words, but deal with phrases ad hoc, for the most part. The number of words is finite (pace Langendoen and Postal in The Vastness of Natural Languages), while the number of phrases is infinite. Morphology describes words, a finite list of things, but syntax must describe the infinity of phrases, so syntax and morphology must differ in a fundamental way.
Sorry I didn't answer your question.