The volatiles emitted from six marine Rhodobacteraceae species of the genus Celeribacter were investigated by GC–MS. Besides several known compounds including dimethyl trisulfide and S-methyl methanethiosulfonate, the sulfur-containing compounds ethyl (E)-3-(methylsulfanyl)acrylate and 2-(methyldisulfanyl)benzothiazole were identified and their structures were verified by synthesis. Feeding experiments with [methyl-2H3]methionine, [methyl-13C]methionine and [34S]-3-(dimethylsulfonio)propanoate (DMSP) resulted in the high incorporation into dimethyl trisulfide and S-methyl methanethiosulfonate, and revealed the origin of the methylsulfanyl group of 2-(methyldisulfanyl)benzothiazole from methionine or DMSP, while the biosynthetic origin of the benzothiazol-2-ylsulfanyl portion could not be traced. The heterocyclic moiety of this compound is likely of anthropogenic origin, because 2-mercaptobenzothiazole is used in the sulfur vulcanization of rubber. Also in none of the feeding experiments incorporation into ethyl (E)-3-(methylsulfanyl)acrylate could be observed, questioning its bacterial origin. Our results demonstrate that the Celeribacter strains are capable of methionine and DMSP degradation to widespread sulfur volatiles, but the analysis of trace compounds in natural samples must be taken with care.

Carbonylation reactions under transition metal catalysis have emerged as one of the most important strategies for the construction of CO inserted molecules having both industrial and material applications. Hence the most widely used protocol for the insertion of CO is by the utilization of CO (gas) but this method limits its applicability in industrial-scale carbonylation due to toxic and explosive nature. To use more cheaper and environmentally benign methods the chemistry of CO surrogates gained considerable attention with the emergence of newer methods and CO surrogates. Aldehydes, formate esters, formamides, and metal carbonyls are the some of the CO surrogates that have been extensively utilized in recent times for the synthesis of industrial bulk chemicals as well in small scale synthesis of pharmacological building blocks. In this review, we have summarized the recent development in carbonylation reactions by utilization of formic acid as CO surrogate.

Six dimethylsulfoniopropionate (DMSP) lyases were shown to cleave the marine sulfur metabolite dimethylsulfoxonium propionate (DMSOP) into DMSO and acrylate. This discovery closes a missing link in the global sulfur cycle.

Pd catalyzed carbonylative reaction of 2-iodo-glycals has been developed taking formic acid as a carbonyl source for the synthesis of 2-carboxylic acids of sugars by the hydroxycarbonylation strategy. The methodology was successfully extended to the synthesis of 2-formyl glycals by using a reductive carbonylation approach. Both ester and ether protected glycals undergo the reaction and furnished sugar acids in good yield which is otherwise not possible by literature methods. The C-2 sugar acids were successfully utilized for the construction of 2-amido glycals, 2-dipeptido-glycal by Ugi reaction and C-1 and C-2 branched glycosyl esters. a Reaction conditions: 1a (0.18 mmol), 2a (0.36 mmol), Pd(OAc) 2 (0.009 mmol), L2 (0.018 mmol), N,N 0 -dicyclohexylcarbodiimide (DCC) (0.18 mmol), triethylamine (0.36 mmol) at 90 C for 2 h. b Yield of isolated product. Pd 5 mol% and ligand 10 mol% were used. Ratio of 3a and 3a 0 and conversion were determined through 1 H NMR.

Two analogues of 3-(dimethylsulfonio)propanoate (DMSP), 3-(diallylsulfonio)propanoate (DAllSP), and 3-(allylmethylsulfonio)propanoate (AllMSP), were synthesized and fed to marine bacteria from the Roseobacter clade. These bacteria are able to degrade DMSP into dimethyl sulfide and methanethiol. The DMSP analogues were also degraded, resulting in the release of allylated sulfur volatiles known from garlic. For unknown compounds, structural suggestions were made based on their mass spectrometric fragmentation pattern and confirmed by the synthesis of reference compounds. The results of the feeding experiments allowed to conclude on the substrate tolerance of DMSP degrading enzymes in marine bacteria.