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Synfacts 2011(3): 0303-0303  
DOI: 10.1055/s-0030-1259470
Metal-Catalyzed Asymmetric Synthesis and Stereoselective Reactions
© Georg Thieme Verlag Stuttgart ˙ New York

Iridium-Catalyzed Enantioselective Cyclopropenation

Contributor(s): Mark Lautens, Norman Nicolaus
M. Uehara, H. Suematsu, Y. Yasutomi, T. Katsuki*
Kyushu University, Fukuoka, Japan
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Publication History

Publication Date:
16 February 2011 (online)

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Significance

Significant effort has been made to prepare substituted cyclopropenes in an enantiomerically pure fashion since they are useful building blocks, which can be further modified in numerous ways. The methodology described herein utilizes chiral iridium(salen) complexes of type 4 and 5 to achieve the enantioselective cyclopropenation of terminal alkynes 2 using different di­azo compounds of type 1 as carbenoid precursors. The cyclopropenation towards the target compounds 3 could be achieved with good to excellent yields and high enantioselectivities.