We report the development of a Pd(II)/(±)-MeO-SOX/2,5-dimethylbenzoquinone system that enables unprecedented access to anti-1,3 amino alcohol motifs in good yields (33 substrates, avg. 66% isolated yield, >20:1 dr) and high selectivities (avg. 10:1 dr). Switching ligands to (±)-CF 3 -SOX using a less bulky quinone oxidant, the kinetic syn-1,3 amino alcohol motif can be accessed in comparable yields and selectivities. Advantages of the stereodivergent nature of this reaction are seen in the synthesis of antiand syn-1,3-amino alcohol vitamin D3 analogue intermediates in half the steps and higher overall yield to previous routes. Additionally, all eight possible stereoisomers of a chiral diamino alcohol core are generated from two amino acids. Mechanistic studies reveal that the anti-isomer is furnished through concurrent Pd(II)(SOX) catalyzed C-H amination and Pd(0)(SOX)-catalyzed isomerization cycles.
Reaction of alk-3-yn-1-ones with non-symmetricalo-phenylenediamines provides an effective method with high atom economy for the synthesis of diversely substituted 1,5-benzodiazepines and conjugated enaminones.
Reaction of alk-3-yn-1-ones with o-phenylenediamines provides an effective method with high atom economy for the synthesis of diversely substituted benzodiazepines and conjugated enaminones. This microwave-accelerated reaction proceeds in ethanol in the absence of a catalyst and leads to benzyl-substituted 1,5benzodiazepines with good yields (70-92%). A room temperature protocol with the same set of reagents (stabilized with triethylamine) leads to enaminones (3-amino-2-alkenones, 70-99%). The tautomer formed and the regio-and stereochemistry of the process are confirmed by the X-ray crystallographic structure determination of 2-(4-methylbenzyl)-4-phenyl-3H-benzo[b][1,5]diazepine and (Z)-3-[(2-amino-4,5-dimethylphenyl)amino]-4-(4-tert-butylphenyl)-1-(4-chlorophenyl)but-2-en-1-one. Scheme 1 The synthesis of 1,5-diazepines 3 from alk-3-ynones 1 and o-phenylenediamines 2. † Electronic supplementary information (ESI) available: 1 H and 13 C NMR spectra for diazepines 3, enaminones 4 and 6, and cif files for 3aa and 4cb. CCDC 929588 and 950049. For ESI and crystallographic data in CIF or other electronic format see
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