Mollenynes B–E from the Marine Sponge Spirastrella mollis. Band-Selective Heteronuclear Single Quantum Coherence for Discrimination of Bromo–Chloro Regioisomerism in Natural Products

Four new chlorobromohydrins, mollenynes B–E, were isolated from the marine sponge Spirastrella mollis collected from Hogsty Reef, Bahamas. Their structures were elucidated by integrated analysis of NMR, MS, and computational methods. A high-resolution band-selective HSQC experiment was developed to identify ¹³C NMR signals in samples at the nanomole-scale that arise from Cl-substituted ¹³C by exploiting the ³⁵Cl/³⁷Cl isotope shift.