@article{thamyongkit_bhise_taniguchi_lindsey_2006, title={Alkylthio unit as an alpha-pyrrole protecting group for use in dipyrromethane synthesis}, volume={71}, ISSN={["1520-6904"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-32144435067&partnerID=MN8TOARS}, DOI={10.1021/jo051806q}, abstractNote={The synthesis of porphyrin precursors requires the successive introduction of substituents at the pyrrole α- and α‘-positions (2- and 5-, respectively). An α-pyrrole substituent that serves as a temporary masking agent and is not deactivating would greatly facilitate such syntheses, particularly for β-(3,4)-unsubstituted pyrroles, but has heretofore not been available. A series of α-RS groups (R = Me, Et, n-decyl, Ph) have been investigated in this regard, including the determination of the kinetics of substitution at the pyrrolic 3-, 4-, and 5-positions and the application to dipyrromethane formation. The RS group was readily introduced into the pyrrole α-position by the reaction of 2-thiocyanatopyrrole (prepared from pyrrole, ammonium thiocyanate, and iodine) and the corresponding Grignard reagent RMgBr. Each 2-alkylthio group activated the pyrrole ring toward deuteration at the 3- or 5- (vs 4-) position. The dipyrromethane synthesis was carried out using a 2:1 ratio of 2-(RS)pyrrole/benzaldehyde with a...}, number={3}, journal={JOURNAL OF ORGANIC CHEMISTRY}, publisher={American Chemical Society (ACS)}, author={Thamyongkit, P and Bhise, AD and Taniguchi, M and Lindsey, JS}, year={2006}, month={Feb}, pages={903–910} }