In the paper we consider the high-level synthesis toolchain for transformation of programs written in C (the standard ISO/IEC 9899:1999) into configuration files of field programmable gate arrays (FPGAs) used in multichip reconfigurable computer systems. Unlike most academic (DWARV, BAMBU, LEGUP) and commercial (CatapultC, Vivado HLS, Vivado Vitis) high-level synthesis tools, "Theseus" uses the original methodology of transformation (porting) sequential calculations into a parallel-pipeline configuration of FPGA hardware. For a sequential program, an information graph is created and transformed into the maximally parallel structure, which is then ported to a specified configuration of the reconfigurable computer system using formal methods of reduction of performance and hardware costs without marking the source text with auxiliary parallelization directives. The distinctive feature of the approach is a significantly smaller number of analyzed variants in comparison to parallelizing compilers. Due to this, it is possible to reduce the porting time of sequential programs in the synthesis of solutions for reconfigurable computer systems with a set of FPGA chips interconnected by a spatial communication system. In the paper we show the results of porting a number of application tasks to the architecture of various reconfigurable computer systems using the proposed "Theseus" toolchain.