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A H 2 O-regulated chemoselective addition in oxa- and aza-Michael reactions for aminoalcohols and mixtures of structurally similar alcohols and amines was reported. The oxa-Michael reactions might be kinetically controlled, and the reactions to produce O-selective products were slowed by the addition of water. The electrophilicity of Michael acceptors and the steric hindrance of Michael donors also affect the ratios of O/N products. This method offers novel ideas over conventional metal-catalyzed or ligand-induced strategies.

A novel method for the construction of 1-azaspirocycles from 5-alkyl-/-arylamine furylcarbinols though intramolecular aza-Piancatelli rearrangement was developed. By using PPh 3 /diethyl azodicarboxylate instead of a Lewis acid, 1-azaspirocyclic compounds were obtained in good yields and the reaction temperature was reduced to room temperature. In addition, substrates with groups that are sensitive to high temperatures or Lewis acids are tolerated under these reaction conditions. This is the first method that is applicable not only to 5-(N-arylaminoalkyl)furylcarbinols with better yields but also to 5-(N-alkylaminoalkyl)furylcarbinols.

A concise and efficient formal synthesis of (-)-hamigeran B is reported. The critical intermediate was synthesized from 3-methoxy-5-methylphenyl trifluoromethanesulfonate with an 11-steps 7.2% total yield route. The chiral quaternary carbon was efficiently and steroselectively constructed through an intermolecular Pauson-Khand reaction and a Claisen rearrangement reaction with >99% ee; the cyclohexane B was then closed through an aldehyde Friedel-Crafts cyclization. Lastly, the isopropenyl group of ring C was introduced through a Suzuki coupling reaction.

A novel and convenient protocol for synthesis of alpha-haloacrylates starting from phosphonium ylide and aldedyde or alcohol was described. Halodimethylsulfonium halide was used for the first time in halogenation of phosphonium ylide. Good yield as well as a high Z/E ratio were shown in representative cases, and an umpolung dimethyl sulfide-ylide species might be involved as an intermediate.

Cyclopenta[c]proline derivatives were synthesized in a stereocontrolled manner and in good yields via catalytic Pauson-Khand reactions. The starting materials, optically pure enyne amino acid derivatives, can be easily prepared by an alkenylboronic acid-mediated Mannich-type reaction. [reaction: see text]

The asymmetric addition of terminal alkynes to alpha-keto ester was carried out using a catalytic amount of (1S,2S)-3-(tert-butyldimethylsilyloxyl)-2-N,N-(dimethylamino)-1-(p-nitrophenyl)-propane-1-ol in the presence of Zn(OTf)(2) to give the corresponding tertiary propargylic alcohols in high yields with up to 94% ee. N-Methylephedrine and Zn(OSO(2)CHF(2))(2) were also examined in this reaction. [reaction: see text]