Cross-coupling of nitrogen with hydrocarbons under fragment coupling conditions stands to significantly impact chemical synthesis. Herein, we disclose a C(sp)-N fragment coupling reaction between terminal olefins and N-triflyl protected aliphatic and aromatic amines via Pd(II)/SOX (sulfoxide-oxazoline) catalyzed intermolecular allylic C-H amination. A range of (56) allylic amines are furnished in good yields (avg. 75%) and excellent regio- and stereoselectivity (avg. >20:1 linear:branched, >20:1 E: Z). Mechanistic studies reveal that the SOX ligand framework is effective at promoting functionalization by supporting cationic π-allyl Pd.

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.

A samarium diiodide promoted tandem β-elimination/cross-pinacol coupling was developed. A series of novel 1-vinyl-1,2-diols with two adjacent quaternary carbon centers were obtained in moderate to good yields. Possible reaction pathways are proposed.1,2-Diols are ubiquitous skeletons that can be found in a wide range of natural products, biologically active molecules as well as medicinally important agents, such as macrolides, polyketides, carbohydrates, and alkaloids. 1 Furthermore, certain 1,2-diol units are also used as efficient building blocks in organic synthesis. 2 Due to these great importance, tremendous efforts have been devoted to the development of methods for efficient synthesis of 1,2-diols. Among them, high efficient construction of 1,2-diol units with broad structural diversity has attracted major attention over the past two decades. For preparation of 1,2-diol units with quaternary carbon stereocenters, however, far fewer reports have appeared in the literature because the establishment of quaternary centers is among the most restrictive in organic chemistry. 3 The reductive coupling reaction between two carbonyl compounds represents a valuable alternative to the osmium tetraoxidemediated dihydroxylation of alkenes for generating 1,2-diols. Typically, SmI 2 -promoted pinacol couplings have evolved significantly over the years to become one of the most useful reactions for the stereoselective preparation of 1,2-diols in acyclic and cyclic systems. 1m,4 Samarium diiodide can effectively promote the intermolecular reductive dimerization of aldehydes or ketones, the so called homocoupling of carbonyl compounds, giving rise to C 2 -symmetrical diols. However, most of the reported relevant pinacol cross-coupling reactions of two different carbonyl compounds were focused on the SmI 2 -mediated intramolecular pinacol couplings. The intermolecular pinacol coupling reaction of two different carbonyl compounds is more challenging and remain relatively unexplored. 5 Furthermore, for preparation of 1,2-diols with two adjacent quaternary carbon centers, however, far fewer reports have appeared in the literature because of the inherent difficulties on quaternary carbon construction. In fact, efficient and straightforward access to asymmetrical 1,2-diols with two adjacent quaternary carbon centers remains a challenging topic in organic synthesis. 1m,4d,6 In the past several years, we have been interested in samarium diiodide mediated reactions for the synthesis of diverse structurally important molecules. 7 We have previously reported two new approaches for the preparation of quaternary carbon-containing α-amino ketone derivatives and 2-quaternary anti-1,3-diol units by SmI 2 -promoted regiospecific electrophilic amination of α-heterosubstituted ketones and tandem aldol/Evans-Tishchenko reaction. 7h,j Concellón et al. showed that the reduction of α-halo-β-hydroxy esters and amides with SmI 2 gives α,β-unsaturated esters and amides with high stereochemical control. 8 Inspired by these results, we envisioned t...

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