The multifaceted nature of supply chains makes financial reconciliation a complex and ever-present issue owing to the challenges of different data storage systems, transaction sequences, and reporting uniformity. Although traditional ERP systems such as SAP S/4HANA promise exceptional transaction management capabilities, they do not provide sufficient visibility, trust, or assurance for real-time reconciliation across different organizations. In this paper, we develop a new framework for integrating blockchain technology into SAP-driven supply chains to enhance financial compliance and automate reconciliation using smart contracts and distributed ledgers. The proposed architecture includes on-chain validation of transactional data, off-chain SAP data mapping, and the use of compliance oracles for regulatory supervision, which allows it to be modular in nature. When tested against conventional methods in a simulated SAP S/4HANA environment using real and synthetic transaction log files, our system achieved a reconciliation cycle time reduction of up to 42%, and a compliance flag detection accuracy improvement of 38%. Moreover, our solution is robust in scalability and multistakeholder traceability, promoting operational efficiency and audit readiness. This research offers a framework for blockchain within enterprise resource planning systems while illustrating how digital trust, transparency, and compliance automation can be strategically adopted in global supply chain finance.