Chiral N-phosphonyl imines were found to be efficient electrophiles for reaction with diethylaluminium cyanide, a non-volatile and inexpensive cyanide source. The reaction produced chiral Strecker adducts, a-aminonitriles, in excellent chemical yields (94-98%) and diastereoselectivities (95 : 5 to >99%). This synthesis was confirmed to follow the GAP chemistry (group-assistant-purification chemistry) process, which can avoid traditional chromatography and recrystallization purifications, i.e., the pure chiral a-aminonitriles bearing a chiral N-phosphonyl group can be simply obtained by washing the solid crude products with hexane. The chiral N-phosphonyl auxiliary can be easily cleaved under mildly acidic conditions and quantitatively recycled by a one-time extraction with n-butanol.The development of efficient synthetic methods that combine economic, environmental and green aspects constitutes a great challenge in modern organic chemistry. 1-4 It has been extremely difficult to find general reagents, particularly chiral reagents, to enable organic synthesis to be performed without the use of traditional chromatography or recrystallization purifications. 5 In fact, chemistry with these advantages has not been established thus far. However, this green concept would encourage the synthetic community to search for such reagents and related reaction processes to better serve the academic and pharmaceutical industry with minimized use of energy, materials and manpower. In the past three years, our research group has discovered that several chiral N-phosphonyl and N-phosphinyl imines suit the above purpose, which led to the new concept of GAP chemistry (group-assistant-purification chemistry). 5 After this concept was generated, we examined and re-examined previous chiral N-phosphonyl and N-phosphinyl imine-based asymmetric reactions 5-9 and found that all of these reactions can be conducted via the GAP chemistry process.Two of the above syntheses involve the asymmetric catalytic Strecker reaction. 5 It is well-known that a-aminonitriles are versatile building blocks for the synthesis of a-amino acids, which belong to the most important building blocks in organic and medicinal chemistry due to their use in protein, peptide and peptidomimetic research. 10,11 In addition, a-aminonitriles are

Computed descriptors for acyclic diaminocarbene ligands are developed in the context of a gold catalyzed enantioselective tandem [3,3]-sigmatropic rearrangement-[2+2]-cyclization. Surrogate structures enable the rapid identification of parameters that reveal mechanistic characteristics. The observed selectivity trends are validated in a robust multivariate analysis facilitating the development of a highly enantioselective process.

The new asymmetric catalytic Strecker reaction of achiral N-phosphonyl imines has been established. Excellent enantioselectivity (95.2-99.7%ee) and yields (89-97%) have been achieved by using primary free natural amino acids as catalysts and Et 2 AlCN as nucleophile. This work also presents the novel use of non-volatile and inexpensive Et 2 AlCN in asymmetric catalysis. The Nphosphonyl protecting group enabled simple product purification to be achieved simply by washing the crude products with hexane. It can also be readily cleaved and recycled under mild condition to give a quantitative recovery of N, N′-bis(naphthalen-1-ylmethyl)ethane-1,2-diamine. A new mechanism was proposed for this reaction and was supported by experimental observations.

A novel multi-component reaction for the synthesis of polyfunctionalized indoles and bis-indoles has been established. The reaction pathways were controlled by varying enamines with different substitution patterns to give polyfunctionalized indoles and bis-indoles selectively. The reaction proceeds at a fast speed within 15–30 min with water as the major byproduct, which makes work-up convenient.

The asymmetric catalytic Strecker reaction of achiral N-phosphonyl imines with Et(2)AlCN has been established. Both free amino alcohols and BINOLs have been proven to be effective catalysts to afford excellent enantioselectivities and yields. The N-phosphonyl group can be readily cleaved under mild conditions and enable purification of crude products by simple washing with hexane. The cleaved N,N-dialkyl diamine auxiliary can be recovered quantitatively via n-BuOH extraction. The scope for both N-phosphonyl imines and catalysts was vastly studied for this new catalytic system.