Macrolactonization of Alkynyl Alcohol through Rh(I)/Yb(III) Catalysis.

A catalytic macrolactonization through oxidative cyclization of alkynyl alcohol by synergistic transition-metal and Lewis-acid catalysis was developed. Because the alkynyl alcohol substrates involved in this method are different from the seco acids that are used in conventional macrolactonization methods, the current method provides a strategically distinct entry to macrolactones. In addition to the operational simplicity, this macrolactonization protocol proceeds at relatively high concentration, precluding the need for high dilution or slow addition procedures.