Subscribe to RSS
DOI: 10.1055/s-0034-1379621
P-Chiral Phosphoramidates from a Catalytic Asymmetric Halocyclization
Brønsted Acid Catalyzed Phosphoramidic Acid Additions to Alkenes: Diastereo- and Enantioselective Halogenative Cyclizations for the Synthesis of C- and P‑Chiral Phosphoramidates.
J. Am. Chem. Soc. 2014;
136: 14734-14737
Publication History
Publication Date:
15 December 2014 (online)
Significance
The Johnston group reports an organocatalytic asymmetric iodocycIization for the synthesis of cyclic phosphoramidates bearing C-and P-chiral centers. The methodology relies on the previously reported catalytic system based on the combination of an achiral Brønsted acid and a chiral enantiopure Brønsted base A. Using N-iodosuccinimide (NIS) as an electrophilic source of iodine, the desired products 2 are obtained under very mild conditions in good yields and in good to excellent enantioselectivities. Notably, if coupled with a simple basic treatment, the transformation is an interesting alternative to asymmetric epoxidations of allylamine derivatives.
#
Comment
Phosphorous-containing compounds largely occur as pharmaceuticals and agrochemicals; thus, significant interest is focused on the development of procedures for their preparation. Interestingly however, despite chirality often being a crucial issue for marketed substances, there is a general lack of catalytic methodologies for the enantioselective synthesis of P-chiral compounds. Here, the authors tackle the challenge disclosing the first organocatalytic protocol for this goal. The synthetic value of the methodology is highlighted by the conversion of the cyclic products into acyclic compounds in a stereospecific process.
#
#