1 3
Topics in Current Chemistry (2019) 377:23
7 Miscellaneous
Very recently, Kim and co-worker [138] developed a gram-scale asymmetric
synthesis of 2,4-diaryl-1-benzopyrans 137 via a one-pot two-step transformation
(Scheme 36). With the aid of (R)-L6, the β-keto acid 135 is efficiently subjected
to a decarboxylative process to provide an enol intermediate 139 at room temperature, which then reacts with ortho-quinone methide 138 in situ generated from
o-hydroxy benzylic alcohol 134 to produce the chiral adduct 136. Subsequently,
Sc(OTf) 3 promotes the cyclization and dehydration sequence to give synthetically
Scheme 36 Enantioselective decarboxylative alkylation of β-keto acids to form chiral benzopyrans
Scheme 37 Nucleophilic substitution reaction of racemic alkyne–dicobalt complexes with thiols
Reprinted from the journal
179
Topics in Current Chemistry (2019) 377:23
7 Miscellaneous
Very recently, Kim and co-worker [138] developed a gram-scale asymmetric
synthesis of 2,4-diaryl-1-benzopyrans 137 via a one-pot two-step transformation
(Scheme 36). With the aid of (R)-L6, the β-keto acid 135 is efficiently subjected
to a decarboxylative process to provide an enol intermediate 139 at room temperature, which then reacts with ortho-quinone methide 138 in situ generated from
o-hydroxy benzylic alcohol 134 to produce the chiral adduct 136. Subsequently,
Sc(OTf) 3 promotes the cyclization and dehydration sequence to give synthetically
Scheme 36 Enantioselective decarboxylative alkylation of β-keto acids to form chiral benzopyrans
Scheme 37 Nucleophilic substitution reaction of racemic alkyne–dicobalt complexes with thiols
Reprinted from the journal
179