Exceptionally mild palladium(II)-catalyzed dehydrogenative C-H/C-H arylation of indolines at the C-7 position under air.

An improved method for the dehydrogenative C-H/C-H cross-coupling at the C-7 position of indolines containing a urea as a directing group is reported. The new protocol is a rare example of an aerobic palladium(II)-catalyzed cross dehydrogenative coupling (CDC) reaction that proceeds at low temperature. The use of either Cu(OAc)2 in an open flask or dioxygen (balloon) at 50 °C tolerates indolines not substituted at C-2 and C-3, thereby extending the scope of the previous method that suffers from indoline-to-indole oxidation.

Formation of three new bonds and two stereocenters in acyclic systems by zinc-mediated enantioselective alkynylation of acylsilanes, Brook rearrangement, and ene-allene carbocyclization reactions.

Diastereoisomerically pure (dr > 99:1) and enantiomerically enriched (er up to 98:2) substituted propargyl diols possessing a tertiary hydroxyl group were synthesized in a single-pot operation from simple acylsilanes through a combined catalytic enantioselective alkynylation of acylsilanes, followed by an allenyl-Zn-Brook rearrangement and Zn-ene-allene (or Zn-yne-allene) cyclization reaction. Two remarkable features of these reactions are the near complete transfer of chirality in the allenyl-Zn-Brook rearrangement and the highly organized six-membered transition state of the Zn-ene-allene carbocyclization found by DFT calculations. In this process, three new bonds and two new stereogenic centers are created in a single-pot operation in excellent diastereo- and enantiomeric ratios.

One-pot zinc-promoted asymmetric alkynylation/brook-type rearrangement/ene-allene cyclization: highly selective formation of three new bonds and two stereocenters in acyclic systems.

It's as easy as 1, 2, 3: In a one-pot sequence, two stereocenters and three new bonds were created with high selectivity through an asymmetric alkynylation of acyl silanes, a tandem Brook-type rearrangement and Zn-ene-allene cyclization, the addition of an electrophile, and finally oxidation. The straightforward nature of the synthetic procedure contrasts strongly with the complexity of the densely functionalized products obtained.