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Transition Metal Catalyst Free Synthesis of Olefins from Organoboron Derivatives **
Author(s) -
Bojaryn K.,
Hirschhäuser C.
Publication year - 2022
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202104125
Subject(s) - stereospecificity , stereoselectivity , stereocenter , organoboron compounds , chemistry , boron , aldehyde , ketone , catalysis , elimination reaction , leaving group , organic chemistry , combinatorial chemistry , stereochemistry , medicinal chemistry , enantioselective synthesis
Stereoselective preparation of highly substituted olefins is still a severe challenge that requires well defined elimination precursors. Organoboron chemistry is particularly suited for the preparation of molecules with adjacent stereocenters. As organo boron substrates with leaving groups in β‐position can undergo stereospecific syn ‐ or anti ‐elimination, this chemistry harbors great potential for the synthesis of complex olefins. In recent years three main strategies emerged, which differ in their approach to the β‐functionalized organoboron elimination precursor. (i) Stereoselective preparation of such elimination precursor can be achieved by addition of a boron‐stabilized anion (d 1 ) to an aldehyde or ketone (a 1 ) or diastereoselective 1,3‐rearrangement of suitable boron‐ate‐complexes. Stereospecific methods rely either on (ii) diastereospecific 1,2‐metalate rearrangement of boron‐ate‐complexes that involve opening of appropriate heterocycles or (iii) addition of chiral carbenoids (d 1 *) to chiral boronates (a 1 *) with a leaving group in α‐position.